A solid having density of

9 x 10³  kg m^-3  forms face centred cubic crystals of edge length  200 √2  pm. What is the molar mass of of the solid

a. 0.0432 kg mol ^-1

b. 0.0305 kg mol ^-1

c. 0.4320 kg mol^-1

d. 0. 0216 kg mol ^-1

Ans. b