Only one of those is a nitrosated aromatic system - the two indolines both have the nitrosamine in non-aromatic rings (though fused to aromatic, yes) and the nitrogen has true single bonds.
1-nitrosoindoline would be category 4 by CPCA:
(0,2) for hydrogen count, and in a generic 5-membered ring, for a total of 5 points.
3-methyl-1-nitrosoindoline would be category 4 as well, with the same features but also the beta-methyl for an activating feature and a total of 4 points
I’m unsure why you were asked to test 2-Methyl-1-Nitroso indole (in an aromatic system and completely lacks a-hydrogens!), but would be really interested to see the data if you do - I’d expect a very different Ames strain profile (TA98/100 +/- S9, as described in Ponting and Foster).