Question

A context-free grammar is ambiguous if

• A. None of the above
• B. it produces more than one parse tree for some sentence
• C. some production has two non-terminals side by side on the right-hand side
• D. the grammar contains useless non-terminals

Answer 1

The correct option is B it produces more than one parse tree for some sentence

A context-free grammar is ambiguous if
1. It produces more than one parse tree for some sentence
or
2.It produces more that one leftmost derivation for some sentence
or
3. It produces more than one rightmost derivation for some sentence.