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: When n is divided by 19, the remainder is 7. When n is divided by 11, the quotient is equal to Z, and the remainder is equal to 7. Z must be divisible by which of the following numbers?

Option A: 16

Option B: 18

Option C: 20

Option D: 19

Option E: 22
Option D

Question: A and B complete a job in 6 days. A alone can do the job in 15 days. If B works alone, how many days will it take to complete the job?

Option A: 8

Option B: 10

Option C: 12

Option D: 14

Option E: 16
Option B

Question: If n is an odd integer, which of the following must also be an odd integer?

Option A: 2n

Option B: 2n^2

Option C: n^2 + 2n

Option D: n^2 + 3n

Option E: n^2 + 2n + 3
Option C