2. (20 points, 4+1 points each) For each NFA below, write a regular expression that represents the language of the machine (4 points). Briefly explain the reasoning for your answer (1 point). (a) = {a,b} -00-00 (b) = {a,b} b 90 91 92 94 (c) = {a,b} -ode - 6 q5 94 (d) = {a,b,c,d} 91 b, c, d 2 92 a, c, d 90 93 a, b, d 94 a, b, c