I will try my best to sovle this question...
Im Pretty sure it has to be A. it needs to balance it would not stand in place if not balanced.
Answer:

Explanation:
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 28.01 17.03
N₂ + 3H₂ ⟶ 2NH₃
m/g: 240.0
(a) Moles of NH₃

(b) Moles of N₂

(c) Mass of N₂

This is an example of a condenser