How many unit cells are present in a cube shaped ideal crystal of $NaCl$ of mass $1.00\;g$ ? <br> [Atomic masses : Na = 23, Cl = 35.5]

Question

( A ) $1.71 \times 10^{21}$
( B ) $2.57 \times 10^{21}$
( C ) $1.28 \times 10^{21}$
( D ) $5.14 \times 10^{21}$