cise $141$ Start with the grammar G$6,$ repeated here:$$G$6$: ::$=+|$ ::$=*|$ ::$=()|$ a $|$ b $|$ c$$Modify it in the following ways: a$.$ Add subtraction and division operators $(-$and $/)$ with the customary prece$-$dence and associativity.$$b$.$ Then add a left$-$associative operator $\%$ between $+$ and $*$ in precedence. c$.$ Then add a right$-$associative operator $=$ at lower precedence than any of the other operators.$$Exercise $2$ Give an EBNF grammar for each of the languages of Exercise $1.$ Use$$the EBNF extensions wherever possible to simplify the grammars. Include what$-$ever notes to the reader are required to make the associativity of the operators clear.