Clarence is a sophomore at Georgetown College. Last year, tuition was $9,390 per semester. This year, he paid $8,451 for each semester. What was the percent of decrease in the cost of tuition?

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