Final answer:
To tighten a nut, you should choose a wrench size that is close to the distance across the nut from one edge to the opposite edge. In this case, the best choice would be 3/8 inch.
Step-by-step explanation:
To choose the right size wrench to tighten a nut, you need to select a wrench size that is close to the distance across the nut from one edge to the opposite edge. In this case, the length of each edge of the nut is 1/4 inch. Therefore, you should choose a wrench size that is close to 1/4 inch. Among the options given, the best choice would be 3/8 inch since it is closest to 1/4 inch.