How many planes of reflectional symmetry does a regular hexagonal prism have?

A regular hexagon has 6 lines of reflectional symmetry, and each line extends through the prism to form a vertical plane of symmetry. The prism also has one horizontal plane halfway between its two bases, which reflects the top half onto the bottom half. Thus, it has 6 + 1 = 7 planes of reflectional symmetry; the correct choice is 7.

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