[tex]\frac{1}{2}^{-2} [/tex] When you have a fraction to a negative power, you flip the number over, and then act like it's to the positive power. So this equals. [tex]\frac{2}{1}^2[/tex]. Now you simply have to evaluate [tex]2^2[/tex], which is 4.
C. 4 (not to be confused with the explosive... :P)