Researchers are interested in the average BMI of all the students in Anschutz medical campus. They used Simple Random Sampling (SRS) method to enroll 200 students in this study. By chance, the average BMI of this sample is different than the true average BMI of all the students in campus. What is the reason for this discrepancy?

Selection bias.

Random sampling error.

Recall bias.

Non-response bias.