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.

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
Option B

Question: A certain car dealership offers its newest model in ten exterior and six interior colors. If the ten interior colors are identical to the ten exterior colors, and the dealership sells every pair of colors except those that would result in a car with an identically colored interior and exterior, how many different color combinations are possible?

 Option A: 45

 Option B: 81

 Option C: 90

 Option D: 10!/2!

 Option E: 36
Option E

Question: In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,6). If a point (a,b) is selected at random from the triangular region, What is the probability that a-b>0?

 Option A: 1/5

 Option B: 1/3

 Option C: 1/2

 Option D: 2/3

 Option E: 4/5

Option D