Which of the following nets, A, B, or C, can be folded to form a cube with a red front face, a green right face, and a blue top face?

Let's assume the central yellow square is the bottom face of the cube.

• If we fold up the red square (to the left of the central yellow), it becomes the front face.
• If we fold up the green square (to the right of the central yellow), it becomes the right face.
• If we fold up the blue square (above the central yellow), it becomes the top face. This arrangement (red front, green right, blue top) perfectly matches the visible faces of the cube shown in the problem.

Let the central yellow square be the bottom face.

• If we fold up the red square (to the right of the central yellow), it becomes the front face.
• If we fold up the green square (to the left of the central yellow), it becomes the left face.
• If we fold up the blue square (above the central yellow), it becomes the top face. In this case, if red is the front, green is the left face, not the right face as in the target cube. So, Net B is incorrect.

Let the central yellow square be the bottom face.

• If we fold up the red square (below the central yellow), it becomes the back face. This does not match the target cube where red is the front. Alternatively, if we try to make red the front, the blue face would be the back, not the top. So, Net C is incorrect.

Let the central yellow square be the bottom face.

• If we fold up the red square (to the left of the central yellow), it becomes the front face.
• If we fold up the blue square (to the right of the central yellow), it becomes the right face.
• If we fold up the green square (above the central yellow), it becomes the top face. In this case, if red is the front, blue is the right face and green is the top face. The target cube has green as the right face and blue as the top face. The positions of green and blue are swapped compared to the target cube. So, Net D is incorrect.

Based on the analysis, only Net A correctly forms the cube with the specified color arrangement.

The final answer is $\text{A}$.