The reduced grammar equivalent to the grammar, whose production rules are given below, is
S → AB | CA
B → BC | AB
A → a
C → a B | b
1.S → CA, A → a, C → b ✓ Correct
2.S → CA | B, B → BC | B, A → a, C → aB | b
3.S → CA | B, B → BC, A → a, C → aB | b
4.S → AB | AC, B → BC | BA, A → a, C → aB | b