To find the y-intercept of the exponential function \( y = \frac{3}{2} (2)^x \), we need to evaluate the function at \( x = 0 \).
Substituting \( x = 0 \):
\[ y = \frac{3}{2} (2)^0 \]
Since \( (2)^0 = 1 \):
\[ y = \frac{3}{2} \cdot 1 = \frac{3}{2} \]
Therefore, the y-intercept of the function is \( \frac{3}{2} \).
So, the correct answer is \( \frac{3}{2} \).