equation $B$:$,\frac{(6\mathrm{.}022{10}^{23}\text{a}\text{t}\text{o}\text{m}\text{s}\frac{?}{\text{m}\text{o}\text{l}})(0\mathrm{.}887(g))}{20\mathrm{.}18\frac{g}{m}ol}=2\mathrm{.}647{10}^{22}$ atoms $($unrounded$)$

After rounding, the answer to equation B should have

$2$ significant figures.

$1$ significant figure.

$4$ significant figures.

$3$ significant figures.

$5$ significant figures.