Each of the pixels can take on one of eight grey levels ranging from 0 (white) to7 (black). In order to prevent sharp discontinuities of shade, the softwaresystem that causes pictures to be displayed enforces the rule that the greylevels of two adjacent pixels cannot differ by more than two. How many of the64 possible assignments of grey levels to two adjacent pixels satisfy this rule? (A) 24 (B) 32 (C) 34 (D) 40 (E) 64