12. (12 points) 17 circles are arranged in a pattern as shown, with a frog starting from the central large circle. Each time, the frog can only jump to an adjacent circle. The number of ways the frog can return to the central large circle after five jumps is ( ).
A. 20
B. 24
C. 28
D. 32
【Solution】Solution: According to the problem, only the following two cases can return to the starting point in five steps. The first case has a total of $2 \times 4=8$ ways, and the second case has $2 \times 8=16$ ways, so there are a total of $8+16=24$ ways.

Therefore, the answer is: $B$.