If f(x) = –x3, g(x) = 3x2 – 1, and h(x) = 2x + 5, what is the degree of [f o g o h](x)?

The degree of a composition is found by multiplying the degrees of the functions, provided their leading terms do not cancel. Here, f has degree 3, g has degree 2, and h has degree 1, so [f ∘ g ∘ h](x) has degree 3 × 2 × 1 = 6. The correct choice is D, 6.

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