Which of the following statements is false?

GATE · 1996 · CS · Question 1 subparts

1. A.

   The Halting Problem of Turing machines is undecidable

2. B.

   Determining whether a context-free grammar is ambiguous is undecidable

3. C.

   Given two arbitrary context-free grammars G1 and G2 it is undecidable whether L(G1)=L(G2)

4. D.

   Given two regular grammars G1 and G2 it is undecidable whether L(G1)=L(G2)

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