The method of dealing with such an exponential function and finding its monotonicity and optimal range is the derivative in higher mathematics, which involves the problem of limit. There is no need for high school students to study specific solutions. The simplest method of multiple-choice questions is the special value method. It is suggested that it be done within 1 minute, and no mistakes will be made.
Take the values of A as -5, -4/9, 0 and 1 respectively, take the typical values of X as-1, 0 and 1 respectively, and get the answer by substitution.