Which statement about ammonia is fully correct?
- AAmmonia acts as a nucleophile by accepting a pair of electrons when it reacts with bromoethane.
- BAmmonia can form a co-ordinate bond with a hydrogen ion to form an ammonium ion.
- CAmmonia is a base and accepts hydroxide ions.
- DThe shape of the ammonia molecule is pyramidal with bond angles of $109.5^\circ$.