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: what is the remainder when 14,452 × 15,652 × 16,781 is divided by 5 ? 
Options: a ) 0 , b ) 1 , c ) 2 , d ) 3 , e ) 4
e

Problem: patrick purchased 60 pencils and sold them at a loss equal to the selling price of 20 pencils . the cost of 60 pencils is how many times the selling price of 60 pencils ? 
Options: a ) 0.75 , b ) 0.8 , c ) 1 , d ) 1.33 , e ) 1.75
d

Problem: how many different pairs of positive integers ( a , b ) satisfy the equation 1 / a + 1 / b = 30 / 51 ? 
Options: a ) 6 , b ) 3 , c ) 2 , d ) 1 , e ) 0

d