A sphere is to be designed with a radius of 2.25 feet. Use differentials to estimate the maximum error when measuring the surface area of the sphere if the possible error in measuring the radius is 0.15 feet. (Hint: The formula for the surface area of a sphere is A(r) = 4r) a.) 63.5426 ft b.) 56.5487 ft c.) 9.5426 ft d.) 8.4823 ft