[12] 3. Consider the following language over alphabet {a,b}: L= {set of strings of length a least 2 that start and end with different characters). For example, strings ab, bbaaa, ababab are in L, while strings aaa, b, baab are not in L. a) Give a context free grammar that generates this language. Try to minimize the number of variables used. b) Give a non-deterministic finite automaton (NFA) that recognizes language L. c) Convert this automaton into context free grammar using formal procedure described in lectures and text