For each of the following, construct regular expressions that match the given set of strings:
(a) Binary strings where every occurrence of a 1 is immediately followed by a 0.
(b) Binary strings where no occurrence of a 00 is immediately followed by a 1.
(c) The set of all binary strings that contain at least one 1 and at most two 0’s.
(d) The set of all binary strings that begin with a 1 and have length congruent to 2 mod 4