I need help with this exercise related to ambiguous grammar and parse trees. For each part a, b, and c, I need a sentence and two different parse trees that match the grammar to show that it is ambiguous.

* Exercise 3 Show that each of the following grammars is ambiguous. (To show that a grammar is ambiguous, you must demonstrate that it can generate two parse trees for the same string.) a. The grammar G4, repeated here: G4: : := + | 1 ( ) | abc b. This grammar: ::= | ::= wilma | betty | : := fred | barney | c. The following grammar for strings of balanced parentheses. (A language of any number of different kinds of balanced parentheses is called a Dyck lan- guage. This type of language plays an interesting role in the theory of formal languages.) ::- 1 ( ) |