The correct option is C White precipitate formed which dissolved in excess aqueous ammonia to form a colourless solution. On heating, a colourless, pungent gas evolved.
The ammonia, being a weak base, produces hydroxide ions in the water.
Zn2+(aq)+2OH−(aq)⟶Zn(OH)2(s)
The zinc hydroxide is the white precipitate.
If you continue to add the ammonia solution the precipitate redissolves because of the formation of the soluble ion Zn(NH3)4 to give a colourless solution. When heated ammonia gas is evolved which is pungent in smell.