7. Please answer TRUE or FALSE for the following statements and give CONCISE explanations.

(a) (2 points) A simple graph is called regular if every vertex of this graph has the same degree. An $n$-cube, denoted by $Q_n$, is a graph that has vertices representing the $2^n$ bit strings of length $n$. Two vertices are adjacent if and only if the bit strings that they represent differ in exactly one bit position. $Q_n$ is regular.

(b) (2 points) Let $V_n$ and $E_n$ respectively be the number of vertices and edges of $Q_n$, the $n$-cube. Then, $E_1 = 1$, $E_2 = 4$, and $E_{n+1} = 2V_n + E_n$.

(c) (2 points) The complete bipartite graphs $K_{2,3}$ and $K_{3,3}$ are planar.