((a)) ** .—** The head of an executive agency may enter into a contract for the procurement of severable services for a period that begins in one fiscal year and ends in the next fiscal year if (without regard to any option to extend the period of the contract) the contract period does not exceed one year.

((b)) ** .—** Funds made available for a fiscal year may be obligated for the total amount of a contract entered into under the authority of this section.