A1. 5 minutes of 45 minutes is $\frac{5}{45}=\frac{1}{9}$.
A1 What fraction of a school hour is the last 5 minutes?
(A) $\frac{1}{9}$
(B) $\frac{1}{8}$
(C) $\frac{1}{6}$
(D) $\frac{5}{12}$
(E) $\frac{1}{3}$