Assume that $n$ copies of unit cubes are glued together side by side to form a rectangular solid block. If the number of unit cubes that are completely invisible is 30, then the minimum possible value of $n$ is:
(A) 204
(B) 180
(C) 140
(D) 84.
Assume that $n$ copies of unit cubes are glued together side by side to form a rectangular solid block. If the number of unit cubes that are completely invisible is 30, then the minimum possible value of $n$ is:\\
(A) 204\\
(B) 180\\
(C) 140\\
(D) 84.