In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: if an integer n is to be selected at random from 1 to 100 , inclusive , what is probability n ( n + 1 ) will be divisible by 5 ? 
Options: a ) 1 / 5 , b ) 1 / 3 , c ) 1 / 2 , d ) 2 / 3 , e ) 2 / 5
e

Problem: if one root of the equation 2 x ^ 2 + 3 x – k = 0 is 5 , what is the value of k ? 
Options: a ) 65 , b ) 79 , c ) 68 , d ) 87 , e ) 90
a

Problem: the sum of first n consecutive odd integers is n ^ 2 . what is the sum of all odd integers between 13 and 31 inclusive . 
Options: a ) 220 , b ) 364 , c ) 410 , d ) 424 , e ) 450

a