A. In determining the Part A taxable income, the Part A adjusted gross income shall be reduced by the following deductions and exemptions.

1. (a) There shall be deducted from the Part A adjusted gross income in determining the Part A taxable income:—

   1. (1) Such net amount of the Part A adjusted gross income of trustees or other fiduciaries subject to taxation under sections nine or ten as is payable to or accumulated for persons not inhabitants of the commonwealth to the extent that such income would not be subject to taxation under section five A if received by a non-resident.
   2. (2) Such net amount of the Part A adjusted gross income of trustees, executors or administrators as is pursuant to the terms of the will, deed or other instrument governing the estate or trust currently payable to or irrevocably set aside for public charitable purposes, or to or for the benefit of any organization or organizations established and operated exclusively for charitable purposes.

2. (b) An exemption shall be allowed under this section equal to the amount by which the total exemptions allowable under Part B of section three exceed the Part B adjusted gross income less the deductions allowable under paragraph (a) of Part B of section three. No exemption shall be allowed hereunder to any married person, other than a married person who qualifies as head of household under section two (b) of the Code, unless a joint return is filed.

   1. (a) There shall be deducted from the Part B adjusted gross income in determining the Part B taxable income:

      1. (1) Such net amount of the Part B adjusted gross income of trustees or other fiduciaries subject to taxation under sections nine or ten as is payable to or accumulated for persons not inhabitants of the commonwealth to the extent that such income would not be subject to taxation under section five A if received by a non-resident.
      2. (2) Such net amount of the Part B adjusted gross income of trustees, executors or administrators as is pursuant to the terms of the will, deed or other instrument governing the estate or trust currently payable to or irrevocably set aside for public charitable purposes, or to or for the benefit of any organization or organizations established and operated exclusively for charitable purposes.
      3. (3) Taxes paid to the United States under the provisions of the Federal Insurance Contributions Act or the Federal Railroad Retirement Act. In no event shall the aggregate of the otherwise allowable deductions of this subparagraph and of all sums deducted from wages as contributions to an annuity, pension, endowment or retirement fund of the United States government, the commonwealth or any political subdivision thereof, attributable to any one taxpayer exceed two thousand dollars.

      4. (4) All sums deducted from wages as contributions to any annuity, pension, endowment or retirement fund of the United States government, the commonwealth or any political subdivision thereof including the optional retirement system established by section forty of chapter fifteen A, provided, that the deduction for such contributions and the deductions otherwise allowable under subparagraph (3) hereof attributable to any one taxpayer shall not in the aggregate exceed two thousand dollars, and any income from any contributory annuity, pension, endowment or retirement fund of the United States government or the commonwealth or any political subdivision thereof, to which the employee has contributed, or any income from a contributory annuity, pension, endowment or retirement fund of any other state or any political subdivision thereof, to the extent that income from any such similar fund established under the laws of the commonwealth is not subject to taxation in such other state or political subdivision.

         [There is no subparagraph (5) to (8).]

   B. In determining the Part B taxable income, the Part B adjusted gross income shall be reduced by the following deductions and exemptions: