The Instantaneous Rate of Appearance of Water from the Reaction $\rightarrow$

The instantaneous rate of appearance of water from the reaction
4 NH₃(g) + 5 O₂(g) $\rightarrow$ 4 NO(g) + 6 H₂O(g)
At some moment in time is 21.3 mmHg/min. What is the instantaneous rate of disappearance of NH₃ at the same moment in time?

A) 10.7 mmHg/min
B) 14.2 mmHg/min
C) 21.3 mmHg/min
D) 32.0 mmHg/min
E) none of these