Which of the following statement is always true? (a)If `f(x)` is increasing, the `f^(-1)(x)` is decreasing. (b)If `f(x)` is increasing, then `1/(f(x))` is also increasing. (c)If `fa n dg` are positive functions and `f` is increasing and `g` is decreasing, then `f/g` is a decreasing function. (d)If `fa n dg` are positive functions and `f` is decreasing and `g` is increasing, the `f/g` is a decreasing function.