What is _2(32)?

The logarithm $\log_2(32)$ asks, to what power must $2$ be raised to get $32$? Since $2^1=2$, $2^2=4$, $2^3=8$, $2^4=16$, and $2^5=32$, the answer is $5$, choice D. Choice A ($4$) is the exponent that gives $16$. Choice C ($16$) is half of $32$, which confuses taking the logarithm with dividing by the base. Choice B ($64$) is $2^6$, or $32\cdot2$, which multiplies instead of finding the exponent. A logarithm is an exponent, so the answer is always much smaller than the number inside.