4. Prove the following grammar is ambiguous: [10 points] Considering a sentence: a+b+c -> -> + | -> a b c

5. Convert the BNF grammar to EBNF [10 points] -> = -> ABC -> + * |() |

6. Convert the following EBNF the equivalent BNF: [10 points]

(a) -> if( ) [else ]

(b) -> {, } 2