I propose to study the relationship between self-esteem and reading skill levels among students at Clairmont High School. At Clairmont, about 14 percent of the student body are seniors, 24 percent are juniors, 30 percent are sophomores, and 32 percent are freshmen. What kind of sampling approach will I be most likely to use? A. Stratified sampling B. Random sampling C. Controlled sampling D. Comparative sampling