When a student multiplied the number 66 by the repeating decimal,

\underline{1} \cdot \underline{a b a b} \ldots=\underline{1} \cdot \underline{a b}

where a and b are digits, he did not notice the notation and just multiplied 66 times 1 . a b. Later he found that his answer is 0.5 less than the correct answer. What is the 2-digit integer \underline{a b} ?

**Answer Choices**

A. 15

B. 30

C. 45

D. 60

E. 75