The athletic department at Hornell High School would like to determine the average height of the 1200 male students at the school.

Select from the following survey methods that would allow the department to draw valid conclusions about the average height of the male students at Hornell High School.
A
Measure the height of every male student at Hornell High School and take an arithmetic average to determine the height.
B
Measure the height of every student on the men's basketball team at Hornell High School and take the arithmetic average.
C
Measure the height of every student on the men's football and men's volleyball teams at Hornell High School and take the arithmetic average.
D
Assign unique student ids to all 1200 male students at Hornell High School. Use a computer program to randomly select 120 male students at Hornel High School, measure their heights and take the arithmetic average.