Find the indefinite integral by the substitution method or state that it cannot be found by our substitution formulas. (If it cannot be found by substitution, enter IMPOSSIBLE. Use C for the constant of integration.)

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