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.

[Q]: Question: The average age of 31 students in a group is 16 years. when teacher's age is included to it, the average increases by one.What is the teacher's age in years?

Option A: 31

Option B: 36

Option C: 48

Option D: 45

Option E: 57
[A]: Option C

[Q]: Question: A six-character password consists of three letter of the alphabet and three different digits between 0 and 9, inclusive. The letter must appear as the second or third character of the password. How many different passwords are possible?

Option A: 5,040

Option B: 2,228,720

Option C: 22,226,000

Option D: 22,237,440

Option E: 22,464,000
[A]: Option E

[Q]: Question: This year, MBB Consulting fired 6% of its employees and left remaining employee salaries unchanged. Sally, a first-year post-MBA consultant, noticed that that the average (arithmetic mean) of employee salaries at MBB was 10% more after the employee headcount reduction than before. The total salary pool allocated to employees after headcount reduction is what percent of that before the headcount reduction?

Option A: 98.5%

Option B: 100.0%

Option C: 102.8%

Option D: 103.4%

Option E: 105.0%
[A]:
Option D