2. Given the quadratic trinomial in $x$ with integer coefficients $a x^{2}+b x+c$, when $x$ takes the values $1, 3, 6, 8$, a student recorded the values of this quadratic trinomial as $1, 5, 25, 50$. Upon checking, only one of these results is incorrect. The incorrect result is ( ).
(A) When $x=1$, $a x^{2}+b x+c=1$
(B) When $x=3$, $a x^{2}+b x+c=5$
(C) When $x=6$, $a x^{2}+b x+c=25$
(D) When $x=8$, $a x^{2}+b x+c=50$
2. (C).

Notice that $(n-m) \mid\left[\left(a n^{2}+b n+c\right)-\left(a m^{2}+b m+c\right)\right]$. From $(6-1) \mid (25-1), (8-6) \mid (50-25)$, but $(81) \mid (50-1)$, this leads to the result being $\mathbf{C}$.