Answer:
The answer is Nitrogen trihydride
Step-by-step explanation:
Ammonia (NH3) contains one atom of nitrogen (N) and three atoms of hydrogen (trihydride).
The options that have hydroxide are wrong because hydroxide (OH) is not found in ammonia. The nitrogen in ammonia is not also referred to as mononitrogen because nitrogen is the anion (N3-) here and it's name is unusually starting the naming process of the compound while hydrogen ion is the cation (H1+)