Number of congruent edges in a cube:

A cube is a three-dimensional solid object that has six congruent square faces. Each face of the cube is a congruent square, and each edge of the cube is a congruent line segment. To find the number of congruent edges in a cube, we need to count the total number of edges.

Step 1: Identify the faces of a cube
A cube has six faces. Each face is a square, and they are arranged in a way that makes the cube symmetrical.

Step 2: Count the edges of a cube
To count the number of edges, we need to understand that each edge is formed by the intersection of two faces. Since a cube has six faces, there are multiple edges formed where the faces meet.

Step 3: Count the edges along each face
Each face of the cube has four edges. So, there are a total of 4 edges on each of the six faces.

Step 4: Total number of edges
To find the total number of edges in a cube, we need to add up the edges along each face. Since there are six faces, we have:
4 edges on the first face + 4 edges on the second face + 4 edges on the third face + 4 edges on the fourth face + 4 edges on the fifth face + 4 edges on the sixth face = 24 edges

Therefore, a cube has a total of 24 edges.

However, the question specifically asks for the number of congruent edges. Congruent edges are edges that have the same length. In a cube, all the edges are congruent because all the faces are congruent squares.

So, the correct answer is A: 12 congruent edges.