$\mathrm {1^{3}+2^{3}+3^{3}+\ldots .+n^{3}=}$ কত?

$\mathrm {\frac{n(n+1)}{2}}$

$\left\{\frac{\mathrm{n}(\mathrm{n}+1)}{2}\right\}^{2}$

$\mathrm {\frac{n(n+1)(2 n+1)}{6}}$

$\mathrm {\frac{n(n+1)^{2}}{4}}$