Any decimal that has only a finite number of nonzero digits is a terminating decimal. If \(a\) and \(b\) are positive integers and \(z=\dfrac{b}{2^a \cdot 5^{2a+1}}\) is expressing as a terminating decimal, how many zeros will \(z\) have between the decimal point and the first nonzero digit to the right of the decimal point?

1) \(a=3\)
2) \(11 < b < 31\)

The OA is C

Source: E-GMAT