Answer: I can see why you put “Tetrahedral”, for it has that Lone Pair of Electrons, and they push the Hydrogens of Ammonia DOWN, but it is the Molecular, not Electronic geometry/conformation That is wanted; so see that sp3 hybridization in your mind, and how the N is “above” the three equidistant Hydrogen atoms, BUT, “ignore“ the Lone Pair; now the Molecule does look like a pyramid, yes? So the answer is trigonal pyramidal.
Explanation:
