Question 3 (6 points) Consider the set of all non-empty bit-strings: {0,1}+ = U{0,134 k=1 Prove that the set {0,1}+ x N is countable. (This set contains all pairs (B,x), where B is a non- empty bit-string, and x is a positive integer. For example, (1011011, 73) is an element of that set.) To answer the question, you can assume without proof that there is a sub-routine printBinStrings (k), which returns a list of all strings in {0,1}", and then terminates. For example, printBinStrings (2) returns the list (00,01, 10, 11)