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: Sum of 19 odd numbers is?

 Option A: 341

 Option B: 351

 Option C: 361

 Option D: 371

 Option E: 381
Option C

Question: Two pipes A and B can separately fill a cistern in 10 and 15 minutes respectively. A person opens both the pipes together when the cistern should have been was full he finds the waste pipe open. He then closes the waste pipe and in another 4 minutes the cistern was full. In what time can the waste pipe empty the cistern when fill?

 Option A: 7

 Option B: 9

 Option C: 5

 Option D: 4

 Option E: 8
Option E

Question: Martin has a business washing cars. Last year he washed 20 cars a
week. This year, he wants to increase his business to 1,200 cars a year.
How many cars will he have to wash each month on average?

 Option A: 200 cars

 Option B: 500 cars

 Option C: 300 cars

 Option D: 100 cars

 Option E: 400 cars

Option D