S1 is True , LALR(1) parsers have same number of states as SLR(1) parsers, but with more power due to lookahead in states.
S2 is True, Any shift-reduce conflict which can be removed by LR (1) can also be removed by LALR(1) .
S3 is True , LALR(1) gains reduce-reduce conflict whereas the corresponding LR (1) counterpart does not have it. This is a proof enough that LALR(1) is less potent than LR (1).
Reference:
[1] www.facweb.iitkgp.ernet.in/~niloy/Compiler/notes/LALRP.doc
hence all S1, S2, S3 are true. Option D is correct .