If the number representing volume and surface area of a cube are equal, then the length of the edge of the cube in terms of the unit of measurement will be

Let the cube edge be a. The volume of a cube is V = a^3 [1] and its total surface area is S = 6a^2. If volume and surface area are equal, a^3 = 6a^2. For a > 0 divide both sides by a^2 to get a = 6. (The solution a = 0 is extraneous for a physical cube of positive edge length.) Hence the edge length of the cube is 6 units, so option 4 is correct. The unit of the edge is the same linear unit consistent with the provided volume and area expressions.

Sources

1. [1] https://www.geeksforgeeks.org/maths/surface-area-of-a-cube-formula/