To find the surface area of a cube, you can use the formula:
\[ \text{Surface Area} = 6s^2 \]
where \( s \) is the length of an edge of the cube.
Given that each edge of the cube is 3 inches long:
\[ \text{Surface Area} = 6 \times (3)^2 \] \[ = 6 \times 9 \] \[ = 54 \text{ square inches} \]
Therefore, the surface area of the cube is 54 square inches. The correct answer is:
C. 54