The volume \( V \) of a cube can be calculated using the formula:
\[ V = s^3 \]
where \( s \) is the length of a side of the cube.
For a cube with a side length of 2 inches:
\[ V = 2^3 = 2 \times 2 \times 2 = 8 , \text{in.}^3 \]
Therefore, the volume of the alphabet block is \( 8 , \text{in.}^3 \). The correct response is 8 in.³.