= 1. Question 1-Regular Expressions Let ni, N2, ..., ng denote the 9 digits of you Student ID. We let {a,b,c} be the alphabet we work with in this question. For each of the languages listed in the parts below, provide description in words or set notation of the language, if the question defines it by a regular expression and provide a regular expression if the question defines the language by a description in words or set notation. For each of the four languages also determine whether the language contains the empty word e and give an example of one word over that is in the language and one such word that is not in the language. Recall that, for a word w, we let |w| denote the length of the word (that is, the number of symbols in w). (a) (ab)* U c(ab)+. (b) 5+09+ U a UbUc (c) {w E * ||w|#n}, where n = n1 + n2 + n3. (d) {w * ||w| is divisible by m}, where m = n1 +na+n4