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 sum of the digits of a two-digit number is 15 and the difference between the digits is 3. What is the two-digit number?

 Option A: 69

 Option B: 78

 Option C: 96

 Option D: Cannot be determined

 Option E: None of these
[A]: Option D


[Q]: Question: A warehouse is labeling computer inventory with 3-digit codes. Each code is to consist of four digits between the numbers 0 and 9. The manager is debating whether to allow any 3-digit codes to have leading zero's before a non-zero number is used. If not allowed, then numbers like0025cannot be used.
The manager wants to measure the magnitude of the number of 3-digit code possibilities that are lost if he disallows the use of leading zero's. How many such codes would be lost?

 Option A: 981

 Option B: 1000

 Option C: 1011

 Option D: 1101

 Option E: 100
[A]: Option E


[Q]: Question: A round table conference to be held between 20 delegates of 20 countries. In how many ways can they seated if two particular delegates are always to sit together?

 Option A: 14!*5!

 Option B: 22!*7!

 Option C: 18!*2!

 Option D: 28!*1!

 Option E: 16!*3!
[A]:
Option C