Which polynomial is prime?

A, B, and C each factor: A has a common factor of 2, while B and C factor by grouping. For D, a cubic polynomial can factor over the integers only if it has a rational root. Testing the possible rational roots (from the Rational Root Theorem) shows none are roots, so D, 9x³ + 11x² + 3x − 33, is prime.

AI-written and checked against the verified answer.