3. Show that the following languages are context-free: (a) {a*b"c" | k, m,n not all equalj (b) {xcy | x, y {a, b)' and rev(x) is a substring of y} In other words: strings that contain a single c character, where the part of the string occurring before c appears reversed somewhere after the c. Example: aaabbcabababbbaaabba is in the language