Which one of the following grammars is free from left recursion?

GATE · 2016 · CS · Set 2 · Computer Science & IT

1. A.

   S → AB
   A → Aa | b
   B → c

2. B.

   S → Ab | Bb | c
   A → Bd | ε
   B → e

3. C.

   S → Aa | B
   A → Bb | Sc | ε
   B → d

4. D.

   S → Aa | Bb | c
   A → Bd | ε
   B → Ae | ε

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