CEMC Fermat, 2000

Algebra Difficulty 2.0 Junior Find the answer Canada

If $P = 3^{2000} + 3^{-2000}$ and $Q = 3^{2000} - 3^{-2000}$ then the value of $P^2 - Q^2$ is

(A) $3^{4000}$ (B) $2 \times 3^{-4000}$ (C) $0$ (D) $2 \times 3^{4000}$ (E) $4$

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