1 . 12+22+32+.....+x2

• A. $\frac{x\left(x+1\right)\left(2x+1\right)}{6}$
• B. $\frac{x\left(x+1\right)}{2}$
• C. $x$
• D. ${\left\{\frac{x\left(x+y\right)}{2}\right\}}^2$

Answer: Option A

Explanation: