There are three schedule options for classes at a high school: 90-minute classes every other day for a year, 90-minute classes every day for a semester, or 45-minute classes every day for a year. out of 1200 students, 50 students from each grade level are chosen at random and asked their preference. identify the population and the sample. a. population: the entire student body sample: 200 students from each grade level c. population: 1200 students sample: 50 students b. population: the entire student body sample: 50 students from each grade level d. population: 1200 students sample: 1200 students