How Many Molecules of XeF₆ are Formed from 12

Multiple Choice

How many molecules of XeF₆ are formed from 12.9 L of F₂ (at 298 K and 2.635 bar) according to the following reaction? Assume that there is excess Xe.
Xe(g) + 3F₂(g) → XeF₆(g)

A) 1.21 × 10²³ molecules XeF₆
B) 8.25 × 10²³ molecules XeF₆
C) 2.75 × 10²³ molecules XeF₆
D) 7.29 × 10²³ molecules XeF₆
E) 1.37 × 10²³ molecules XeF₆