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: In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?

 Option A: 1/3

 Option B: 2/5

 Option C: 3/7

 Option D: 8/27

 Option E: 9/29
Option A

Question: What does the hexa number E78 in radix 7.

 Option A: 12455

 Option B: 14153

 Option C: 14256

 Option D: 13541

 Option E: 14541
Option D

Question: The operation T is defined by x T y=1/x+1/y for all nonzero numbers x and y. If z is a number greater than 1, which of the following must be true.
I. x T (-z)=0
II. z T z/z-1=z
III. 2/z T 2/z=1

 Option A: a.

 Option B: b.

 Option C: c

 Option D: d

 Option E: e

Option E