Answer: D. unenforceable contract.
Explanation:
If a contract is valid yet is prohibited from being enforced by a statute of limitation then the contract is simply unenforceable.
The parties involved in the contract can still perform the duties that were assigned to them by the contract but because it is not enforceable, if either party fails to carry out their side of the contract, the other cannot take them to court because the court will not enforce it.
