1. For each part below, give the context-free grammar that generates the language specified. 20 points a) 4-wEo.tarts and ends with different symbols, has at least three Os, and is of even length b)1,-{w#x #y#21 w, is a substring of: and' is a substring ofy and w x, y, z e { 047 , where s" is the reverse of string s o) L fab'e i k where i, j,k 20, or j 2 3 where i,k 0 d) Complement of L o1i j where i,j20