Answer:
The correct answer is letter "A": Option contract.
Step-by-step explanation:
An option contract gives a buyer the right but not the obligation to purchase an asset at a certain price -usually fixed- and date. The term is mostly used while talking about stocks. A buyer can profit both from the upward and downward movements of the stock price. If the price goes up, the investor could bet on call options while the decreasing price could allow investors to profit from put options.
Lucas's case reflects an option contract because he is planning to purchase a house from Janet at a price and date in the future but he agreed in not having the obligation to buy the house when that date arrives.