If a population is a sample of the population could be
O A. ninth-graders at Peak School; all students at Peak School
B. math teachers; the entire school faculty
O C. people who purchased shoes; all customers
O D. all citizens; registered voters

Definition: A sample is a smaller part of the whole, i.e., a subset of the entire population. It is representative of the population in a study. When conducting surveys, the sample is the members of the population who are invited to participate in the survey. Hence said, a sample is a subgroup or subset within the population.

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)

its 50 miles away from the starting point