CNF doesn't allows ε-productions
first we've to eliminate ε-productions
A->B | AB | BA | BB | ε
B->00
the language contains ε so A->ε can't be eliminated
Eliminating unit productions
A->00 | AB | BA | BB | ε
B->00
Now converting to CNF
A->CC | AB | BA | BB | ε
B->CC
C->0