Suppose that an instructor assigns different letter grades based on points earned on a 10-point quiz, and that all scores have been verified to be between 0 and 10 inclusive. also suppose that four possible letter grades can be assigned and that 9 or 10 points is an a, 7 or 8 points is a b, 6 points is a c, and 5 or fewer points is an f. to assign letter grades, the most efficient numeric array containing point values would contain elements. a. tenb. fivec. fourd. three