8) For every natural number $n$, we denote by $S_{n}$ the sum of the first ten multiples of $n$: for example, $S_{2}=2+4+6+8+10+12+14+16+18+20$. What is the value of $S_{1}+S_{2}+S_{3}+\ldots+S_{10}$?
(A) 2925,
(B) 3025,
(C) 3125
(D) 3225
(E) 3325.
8. The answer is $(\mathbf{B})$.

For any fixed natural number $n$ we have

$$
S_{n}=n+2 n+\cdots+10 n=n(1+2+\cdots+10)=n \cdot 55 .
$$

Therefore

$$
S_{1}+S_{2}+\cdots+S_{10}=55(1+2+\cdots+10)=55 \cdot 55=3025 .
$$