$32 \cdot 16$ The number of digits of the number $N=2^{12} \cdot 5^{8}$ is
(A) 9.
(B) 10.
(C) 11.
(D) 12.
(E) 20.
(22nd American High School Mathematics Examination, 1971)
［Solution］ Reorganize the factors
$$
N=2^{4}\left(2^{8} \cdot 5^{8}\right)=16 \cdot 10^{8}=1600000000 \text {, }
$$

It is a ten-digit number.
Therefore, the answer is (B).