(b) Transition rules. -- The exemption from payment of tax on purchases of tangible personal property or taxable services directly used or consumed in the activity of contracting, as defined in section two of this article, which expires as of March 1, 1989, shall nevertheless remain in effect with respect to:
- (1) Tangible personal property or taxable services purchased by a contractor on or after said first day of March in fulfillment of a written contract for contracting, as defined in section two of this article, that was executed and legally binding on the parties thereto on or before February 15, 1989; or in fulfillment of a written contract entered into after February 15 pursuant to a written bid for contracting that was made on or before February 15 that was binding on the contractor, but only to the extent that the bid is subsequently incorporated into a written contract; or
- (2) Tangible personal property or taxable services purchased by a contractor on or after March 1 pursuant to a written contract executed on or before February 15, 1989, to purchase in specified quantities identified tangible personal property or specified taxable services; or
- (3) Tangible personal property or taxable services purchased by a contractor for consumption or use in fulfillment of a written contract entered into before September 1, 1989, when such contract is for the construction of a new improvement to real property the construction or operation of which was approved by a federal or state regulatory body prior to February 1, 1989, or pursuant to a federal grant awarded prior to such first day of February.