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: Find the equation of a line which passes through A(4, -1) and is parallel to x axis.

 Option A: y=-2

 Option B: y=3

 Option C: y=2

 Option D: y=-1

 Option E: y=0

A: Option D
****
Q: Question: The number of diagonals of a polygon of n sides is given by the formula z=n(n-3)/2. If a polygon has twice as many diagonals as sides, how many sides does it have?

 Option A:  3

 Option B:  5

 Option C:  6

 Option D:  7

 Option E:  8

A: Option B
****
Q: Question: The operation # is defined for all nonzero w and y by w#y = w + w/y. If a>0, then 1#(1#a) =

 Option A: a

 Option B: a+1

 Option C: a/(a+1

 Option D: (a+2

 Option E: (2a+1

A:
Option E
****