Explanation

This problem is about permutations, because the order of the figurines matter since they each look unique.

You have two cases to consider here. Start with the option that Margaret buys three witches and three ghosts. In that case, she has 3 choices of witch for the first spot, 3
choices of ghost for the second spot, 2 choices of witch for the third spot, 2 choices of ghost for the fourth spot, 1 choice of witch for the fifth spot, and 1 choice of ghost for the sixth spot:

Hence, her total number of arrangements is 3 × 3 × 2 × 2 × 1 × 1 = 36, which is choice (C). If she buys four of each figurine, her number of arrangements is 4 × 4 × 3 × 3 × 2 × 2 × 1 × 1 = 576, choice E.

Hence options C and E are correct!
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Sandy
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