You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

[EX Q]: Question: If k and w are the dimensions of a rectangle that has area 21, and if k and w are integers such that k > w, what is the total number of possible values of k?

 Option A:  Two

 Option B:  Three

 Option C:  Four

 Option D:  Five

 Option E:  Six
[EX A]: Option A

[EX Q]: Question: A boy and a girl appear for an interview against 2 vacant posts in an office. The probability of the boy's selection is 1/5 and that of the girl's selection is 1/3. What is the probability that only 1 of them is selected?

 Option A: 1/3

 Option B: 2/5

 Option C: 3/5

 Option D: 4/7

 Option E: 5/9
[EX A]: Option B

[EX Q]: Question: In a two-digit, if it is known that its unit's digit exceeds its ten's digit by 2 and that the product of the given number and the sum of its digits is equal to 144, then the number is?

 Option A: 12

 Option B: 24

 Option C: 36

 Option D: 38

 Option E: 40
[EX A]:
Option B