How many more resonating structures does aniline have than anilinium ion?

3

The correct answer is option 2. 3.

Aniline has five resonating structures, out of which three of them have a positive charge on nitrogen. This results in unavailability of electron pair for protonation. When aniline accepts a proton, it forms anilinium ion which has only two resonating structures and is less stable and more basic than aniline.

The resonating structures of aniline : 

Resonating structures of Anilinium ion: