Which one of the following statements is FALSE?

GATE · 2004 · IT

1. A.

   There exist context-free languages such that all the context-free grammars generating them are ambiguous

2. B.

   An unambiguous context free grammar always has a unique parse tree for each string of the language generated by it.

3. C.

   Both deterministic and non-deterministic pushdown automata always accept the same set of languages

4. D.

   A finite set of string from one alphabet is always a regular language.

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