How Many Molecules Are in a Sample of Water, H₂O

How many molecules are in a sample of water, H₂O, which has a mass of 50.0 g?

A) 1.67 x 10²⁴ molecules
B) 5.42 x 10²⁶ molecules
C) 2.16 x 10²³ molecules
D) 3.01 x 10²⁵ molecules
E) 8.30 x 10^-23 molecules