“Security” includes, but is not limited to, the following:
(a) A note endorsed by any member of the credit union or by any other person.
(b) Any obligation wherein the payment of interest and principal is guaranteed by any municipal government, state government, the government of the United States, or by any instrumentality of the United States.
(c) The amounts which a member has invested in the credit union, either in the form of shares or in funds received. If the amount invested by a member is equal to the loan made to that member, he shall not be required to give further security.