1. If $a, b, c$ are 3 different positive integers, and $a b c=16$, then the maximum possible value of $a^{b}-b^{c}+c^{a}$ is ( ).
(A) 249
(B) 253
(C) 263
(D) 264
$-1 . C$.
From the given, we easily know that $\{a, b, c\}=\{1,2,8\}$.
And when $b=1, c=2, a=8$, $a^{b}-b^{c}+c^{a}$ reaches the maximum value $8-1+2^{8}=263$.