If an integer n is to be selected at random from 1 to 105, inclusive, what is probability n(n+1) will be divisible by 7?	Choose the most appropriate option.
A) 1/7	B) 3/14	C) 1/2	D) 2/7	E) 3/4
For n(n+1) to be a multiple of 7, either n or n+1 has to be a multiple of 7.   Thus n must be of the form 7k or 7k-1.   The probability is 2/7.   The answer is 2/7.
<result>D</result>
If an integer n is to be selected at random from 1 to 105, inclusive, what is probability n(n+1) will be divisible by 7?