I think example of A is wrong ... it will be { WW^{r }: W ∈(a,b)^{+ }and W^{r } is reverse} ... correct me if i am wrong ...

Edit : { WW^{r }: W ∈(a,b)^{* }and W^{r } is reverse} ... both r npda .... My mistake ...

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Which of the following statements is true?

- If a language is context free it can always be accepted by a deterministic push-down automaton
- The union of two context free languages is context free
- The intersection of two contest free languages is a context free
- The complement of a context free language is a context free

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