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: Each of the integers from 0 to 9, inclusive, is written on a separate slip of blank paper and the ten slips are dropped into hat. If the slips are then drawn one at a time without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 9?

 Option A: 2

 Option B: 3

 Option C: 1

 Option D: 6

 Option E: 4
Option D

Question: If the charge of staying in a student youth hostel $18.00/day for the first week, and $15.00/day for each additional week, How much does it cost to stay for 23 days?

 Option A: $336

 Option B: $289

 Option C: $282

 Option D: $274

 Option E: $286
Option A

Question: If n is the greatest positive integer for which 4^n is a factor of 10!, then n =?

 Option A: 2

 Option B: 4

 Option C: 6

 Option D: 8

 Option E: 10

Option B