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: In a class of 40 students, 10 did not opt for math. 15 did not opt for science and 2 did not opt for either. How many students of the class opted for both math and science?

 Option A: 13

 Option B: 15

 Option C: 7

 Option D: 17

 Option E: 18
[EX A]: Option C

[EX Q]: Question: There are 4 boys and 3 girls seated in a row.Find the probability that all girls are together?

 Option A: 1/6

 Option B: 1/7

 Option C: 2/7

 Option D: 3/7

 Option E: 4/7
[EX A]: Option B

[EX Q]: Question: An office supply store stocks two sizes of notebooks, each in five colors: blue, green, yellow, red, or pink. The store packs the notebooks in packages that contain either 4 notebooks of the same size and the same color or 4 notebooks of the same size and of 4 different colors. If the order in which the colors are packed is not considered, how many different packages of the types described above are possible?

 Option A: 10

 Option B: 12

 Option C: 20

 Option D: 24

 Option E: 28
[EX A]:
Option C