If I am correct, this grammar accepts no string at all. because in the first production itself, it can be clearly seen that B is the symbol which is there in both the productions of S symbol and there is no production of B which leads S somewhere. But, for the sake of completeness, I am including my solution. Hope it would be of some help!

The grammar derived after elimination is still not in CNF.

CNF corresponds to

A -> BC or A -> a

where A,B,C are in V , and a is in T.

Production S -> ABC violates the rule.