Instructions: 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'.
Input: Problem: the average weight of 8 person ' s increases by 2.5 kg when a new person comes in place of one of them weighing 50 kg . what might be the weight of the new person ? 
Options: a ) 70 kg , b ) 80 kg , c ) 85 kg , d ) 90 kg , e ) 95 kg
Output:
a