The logarithm that is expanded correctly is ㏒₉ 7/(ab)² = log₉ 7 - 2log₉ b - 2log₉ b. It follows the law of logarithm for a fraction, log (a/b) = log a - log b, for a monomial, log ab = log a + log b and for a variable with exponent, log a² = 2log a. The answer is therefore letter C. The rest of the answers are not properly expanded.