What is the maximum length of time a CO use to insert the date in (d)? I.e,how long past the expiration of an indefinite-delivery, indefinite-quantity contract can a delivery order expire?
The answer is found at DFARS 217.204: "...the ordering period of a task order or delivery order contract (including a contract for information technology) awarded by DoD pursuant to 10 U.S.C. 2304a—
(A) May be for any period up to 5 years;
(B) May be subsequently extended for one or more successive periods in accordance with an option provided in the contract or a modification of the contract; and
(C) Shall not exceed 10 years unless the head of the agency determines in writing that exceptional circumstances require a longer ordering period.
Task orders may be performed up to five years (one-year base plus four one-year options) past the basic contract expiration date only when the order is issued before the basic contract expiration date."
In other words, the task order itself can add a period of performance of up to five years past the expiration date of the basic contract. Note that DFARS 217.204 contains some exceptions to this authority.