Final answer:
Jack's decision to make more chocolates in February is based on the economic concept of law of supply.
Step-by-step explanation:
Jack's decision to make more chocolates in February is based on the economic concept of law of supply. The law of supply states that as the price of a good increases, suppliers are willing to produce and sell more of that good. In this case, Jack expects the price of chocolates to increase around Valentine's Day, so he prepares to make more chocolates in February to take advantage of the higher prices.