4. Each of the following English language statements describes a language over the binary alphabet. Write each one as a set using set-builder notation (in other words, set notation using a rule). You may define new functions if they are helpful in simplifying your answer. a. The set of all binary strings that contain at least one 0 and at least one 1. b. The set of all binary strings with even length. c. The set of all binary strings that contain an even number of 1's. d. The set of all binary strings that read the same forward and backwards (in other words, the set of all binary palindromes). Note that the "reverse" notation at the top of page 14 in the book is very useful here