You will be given a definition of a task first, then some input of the task.
In this task, you are given a question containing a blank (_) and two options. You should pick the best option to answer the question. Please answer with "A" or "B".

Fred takes two different supplements, vitamins when he goes to the gym and protein when he goes running. He took the _ last night when he went running. (A) vitamins (B) protein
Output:
B