Let G be a context-free grammar where G = ({S, A, B, C}, {a, b, d}, P, S) with the productions in P given below.
S → ABAC
A → aA ∣ ε
B → bB ∣ ε
C → d
(ε denotes the null string). Transform the grammar G to an equivalent context-free grammar G′ that has no ε productions
and no unit productions. (A unit production is of the form x → y, and x and y are non terminals).