In how many ways can two integers be selected from 60 consecutive positive integers so that their sum is even?

It should be a or d i’m not sure

So don't take my word i'm not exactly a mathematical person but i would assume a. because while selling the soap every month you increase in sells so you would by 11 percent. the you would get the factor 0.89 which if i had to guess would be the monthly profit over 11 probably wrong tho