Exercise 2 Give an EBNF grammar for each of the languages of Exercise 1. Use the EBNF extensions wherever possible to simplify the grammars. In particular, you should eliminate explicit recursion from the grammars wherever Don't forget to put single quotes around any EBNF metasymbol when using it as a token possible. There are often many correct answers. a. The set of all strings consisting of zero or more as. b. The set of all strings consisting of an uppercase letter followed by zero or more additional characters, each of which is either an uppercase letter or one of the digits O through 9. c. The set of all strings consisting of one or more as. d. The set of all strings consisting of one or more digits. (Each digit is one of the