The principal of a large high school wants to learn about student opinion regarding remote learning versus in person learning. Each of the following methods introduces a possible source of bias. Name the type of bias . a. The principle selects a random sample of students from those who signed up for remote learning. b. The student emails a random sample of 100 students, but only 28 students respond . c. The principal surveys the first 50 students that submit their learning preference for the upcoming school year.