Write regular expressions to match the following criteria and only the following criteria. Write regular expressions only, not Ruby code.

(a) Any string that contains an integer comprised of 3n + 1 digits, for n e N for example, these string match: "ur 8", "4002", "Ticket #3435947". These do not: "44th ain't bad.", "div-921", "[10230]"

(b) Any string whose entire contents are a septendecimal (Base-17) literal. Allow for either upper or lowercase letters.

(c) Any string that contains a block of test that begins with $$ and ends with $$. Match only a single block

(d) Any string whose entire contents are one the form CITY, State ZIP. STATE is a two letter state abbreviation. ZIP is either a 5-digit or ZIP+4 ZIP code. Capture the three pieces of information and only those three. For example, matching "Madison, New York 54703-1204" should capture "Madison", "NY", and "54703-1204"

(e) Any string that contains a sequence of space of tab characters at the end of a line. Match the whole sequence Such trialing spaces are a scourge.