How many faces does an open cube have?

Given: - an open cube box

To find the number of faces in an open cube box.

In an open cube box, one of the faces of a cube is missing. Therefore, the number of faces required to form an open box is only 5.

On unfolding the given open cube box and counting the number of faces, we get: -   

                                                                                  No. of faces $=5$

Hence, the number of faces in an open cube box is $6-1=5$ faces and the correct option is option C.