Which of the Following Statements About Governmental Contracts Is True

Which of the following statements about governmental contracts is true?

A) Promissory estoppel can be used to allow a bidder to withdraw a bid but impose a penalty.
B) Governmental contracts are generally covered by statute.
C) The rules governing governmental contracts give the entity discretion as to who to award the contract to.
D) The rules governing governmental contracts allow parties to withdraw bids without penalty.