If the radius r of a spreading circular rash is increasing at a rate of 0.3 cm/day, then the area A = 172 of the rash increases at a rate of ......... cm2/day when the radius of the rash is 5 cm. Note: ris a function of t (time) a) 2.4n Ob) 37t c) 3.671 O d) 4.8nt Oe) None of the above