3. Write regular expressions over the vocabulary {0, 1} for each of the following: a. All strings consisting of a possibly empty sequence of a's followed by a non-empty sequence of 1's. b. All strings which, when interpreted as binary numbers, represent all non-negative numbers divisible by 8. C. All strings representing positive binary numbers n without leading zeros such that there exist positive integers a, b and c with a" + b = ch