“Security” means every instrument commonly known by that term, except:

1. (a) Commercial paper when issued, given or acquired in a bona fide way in the ordinary course of legitimate business, trade or commerce.
2. (b) Promissory notes, whether secured or unsecured, if not offered to the public, and if not sold to an underwriter of the sale for the purpose of resale.
3. (c) Mortgage participation certificates issued under and in accordance with the provisions of Chapter 2, Part 6, Division 2.
4. (d) Policies of insurance issued by an insurer.