Final answer:
To make 1/2 of the batch of bread, you would need 6 1/2 cups of butter.
Step-by-step explanation:
To find out how much butter you need for 1/2 of the batch, you can multiply the amount of butter needed for the full batch by 1/2. The recipe calls for 13 cups of butter for the full batch, so for 1/2 of the batch you would need:
13 cups × 1/2 = 6 1/2 cups
So the correct choice is 6 1/2 cups (option b).