Answer the following questions on ordered pairs and Cartesian products:
a. (i) Define an ordered pair and give one illustrative example using numbers.
b. (ii) Define the Cartesian product of two non-empty sets A and B, and state the formula for the number of elements in A×B when both sets are finite.
c. (iii) State, with an example, whether A×B and B×A are always equal. Justify your answer in one or two sentences.