Question 6 (26 points) Consider the following CFG for binary numbers. B + 2 B. twice = false B + NM Z +0 N +1 M + ZM M + NM M + (a) Augment this grammar with attribute rules that will accumulate true into a twice at- tribute of the root of the parse tree if the string contains at least twice as many ls as Os, and false otherwise. (b) Is your attribute grammar S-attributed