8. E.

Let $0 . \dot{a} \dot{b}=\frac{\overline{a b}}{99}, 0 . \overline{a b}=\frac{\overline{a b}}{100}$.
Let $x=\overline{a b}$. Then
$$
\begin{array}{l}
66\left(1+\frac{x}{100}\right)+0.5=66\left(1+\frac{x}{99}\right) \\
\Rightarrow x=75 .
\end{array}
$$
8. A student multiplies 66 by the repeating decimal
1. $a b a b \cdots=1 . \dot{a} \dot{b}(a 、 b$ are two digits $)$, but the student doesn't notice the repeating part and incorrectly multiplies 66 by 1. $\overline{a b}$, later finding that the result is 0.5 less than the correct answer. Then the two-digit number $\overline{a b}$ is ( ).
(A) 15
(B) 30
(C) 45
(D) 60
(E) 75