The BEST Way to Select a Random Sample of 10

The BEST way to select a random sample of 10 students from a class would be to:

A) choose the first 10 who enter the classroom.
B) choose the last 10 who leave the classroom.
C) write each student's name on a piece of paper, put the papers in a pile, close eyes, and pick 10 papers.
D) ask students their ethnicity, grade-point average, and academic major, and then be sure the sample reflects all of these student characteristics.