Study the following expressions and answer the questions that follow.
a. (i) Prove that 12 is an irrational number.
b. (ii) Using the result of part (i), determine whether 3+12 is rational or irrational. Provide a valid reason.
c. (iii) Identify the smallest set among N,W,Z,Q,irrational numbers,R that contains the number 73+12.