Which polynomials are in standard form?

A polynomial is in standard form when its terms are written in descending order of exponent, with like terms combined. A has exponents 2, 1, and 0; D has exponents 4, 3, 2, and 0; and E has exponents 3, 2, and 1. Those are in standard form. B and F have terms out of order, while C has like terms, 4a and a, that have not been combined.

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