Hello
A chiral carbon atom is an atom that is attached to four different groups of atom. In the 3 structures given, only two atoms have a chiral center.
I'll proceed to draw the structure and indicate the chiral atom below.
If we look at this chiral carbon, we would notice some different in this particular carbn atom and that it is surrounded by 4 different carbon atoms namely
If we carefully look at this, we would see that it is bonded with CH₂, H, NH₂ and COO
In the second structure, we can see that there's no carbon atom that possess this distinctive and unique characteristic of a chiral center.
Lastly, in this compound, we have a carbon atom with one chiral center which is the second carbon atom. Just like in the pervious question above, it is surrounded by CH₂, H, NH₂ and COOH atoms and this makes it a chiral center.
In the question given, only compound 1 and 3 have one chiral carbon atoms.