Based on the context provided in Document B, the person who could NOT get a refund for his or her SlimFit backpack would be:
B. John, who is not happy with the colors of the backpack.
Typically, dissatisfaction with color choices does not qualify for a refund unless stated otherwise in the refund policy. The other options could potentially fall under more typical return reasons, like purchasing conditions (A and D) or timing (C if the return policy allows returns within 60 days). Without further details on the refund policy, John’s reason for wanting a refund would likely not be sufficient.