已知等差数列 $\left\{a_{n}\right\}$ 前 9 项的和为 $27, a_{10}=8$, 则 $a_{100}=$ ( )
等差数列 $\left\{\mathrm{a}_{n}\right\}$ 前 9 项的和为 $27, \mathrm{~S}_{9}=\frac{9\left(a_{1}+a_{9}\right)}{2}=\frac{9 \times 2 a_{5}}{2}=9 \mathrm{a}_{5} . \therefore 9 \mathrm{a}_{5}=27, \mathrm{a}_{5}=3$, 又 $\because \mathrm{a}_{10}=8, \therefore \mathrm{d}=1, \therefore \mathrm{a}_{100}=\mathrm{a}_{5}+95 \mathrm{~d}=98$, 故选 $: \mathrm{C}$.