Final answer:
The story problem that represents the division 1/2 ÷ 2/5 is option A: Mary had half a pizza, and she shared it with her two friends. Each friend got 2/5 of the pizza.
Step-by-step explanation:
The story problem that represents the division 1/2 ÷ 2/5 is option A: Mary had half a pizza, and she shared it with her two friends. Each friend got 2/5 of the pizza. This problem matches the given division because we have a quantity (half a pizza) divided into equal parts (2/5) to find out how much each friend gets.