Which expressions are perfect cubes?

A perfect cube has a numerical factor that is a cube and variable exponents that are multiples of 3. Since −1,000 = (−10)³, 27r²¹ = (3r⁷)³, and g³h³⁰ = (gh¹⁰)³, choices A, B, and D are perfect cubes. Also, −1 = (−1)³, so E is a perfect cube. Choice C, 343p, has a variable exponent of 1, so it is not a perfect cube in general.

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