Final answer:
The correct answer is D. Option contract. An option contract in legal terms is an agreement where one party keeps an offer open for a specific period in exchange for consideration.
Step-by-step explanation:
The question describes a contractual proposal that must be in writing, be signed by a merchant, and must specify the period it is set to remain open. The correct answer is D. Option contract. An option contract is an agreement between parties that gives one party (the buyer) the right to perform a transaction with another party (the seller) at a later date, at a predetermined price. In the context of employment, after you negotiate your job offers, including salary and starting dates, you may enter into an employment contract, which would also be subject to negotiation and could include provisions similar to an option contract, like the duration of the contract.