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 integers a and b are distinct factors of 30, which of the following CANNOT be a factor of 30?
I. ab + b^2
II. (a + b)^2
III. a + b

 Option A: I only

 Option B: II only

 Option C: III only

 Option D: I and II only

 Option E: I, II, and III
[EX A]: Option B

[EX Q]: Question: A company consists of 5 senior and 3 junior staff officers. If a committee is created with 3 senior and 1 junior staff officers, in how many ways can the committee be formed?

 Option A: 12

 Option B: 30

 Option C: 45

 Option D: 80

 Option E: 200
[EX A]: Option B

[EX Q]: Question: If P (A) = 0.18, P (B) = 0.5 and P (B|A) = 0.2, find P(A n B)?

 Option A: 0.36

 Option B: 0.4

 Option C: 0.42

 Option D: 0.43

 Option E: 0.64
[EX A]:
Option A