Which expression can be used to approximate the expression below, for all positive numbers a, b, and x, where a Not-equals 1 and b Not-equals 1? log Subscript x Baseline x StartFraction log Subscript b Baseline x Over log Subscript b Baseline a EndFraction StartFraction log Subscript b Baseline a Over log Subscript b Baseline x EndFraction StartFraction log Subscript a Baseline b Over log Subscript x Baseline b EndFraction StartFraction log Subscript a Baseline x Over log Subscript b Baseline x EndFraction