Given a prompt and four completions, select the completion that is the most plausible in continuing or answering the prompt. This task is designed to test common sense and has various categories ranging between idioms, negated statements, polysemy, subject referencing, and quantitative reasoning. Generate either Completion A, Completion B, Completion C, or Completion D.

Prompt: A cashier is helping a customer. They
Completion A: don't believe in Mondays but do believe in the customer.
Completion B: apply the store's discount.
Completion C: ring a bell, play Jenga, and smack the customer.
Completion D: run around the store, screaming, disregarding the customer.
Completion B