Suppose $a$ and $b$ are positive constants. If $a < b$, then which is larger?

(a) $a^{2}$ ? is less than is greater than $b^{2}$

(b) $a^{-2}$ ? is less than is greater than $b^{-2}$

(c) $a^{1/2}$ ? is less than is greater than $b^{1/2}$

(d) $a^{-1/2}$ ? is less than is greater than $b^{-1/2}$