Dr. Pule is conducting a research study of undergraduate students at her university. She wants to ensure an equal number of students from each year level, so she uses the list of all students provided by the university. From each list, she randomly selects 50 students from each group. What strategy of sampling is Dr. Pule using?

Dr. Pule is using **A. Stratified random sampling**.

In this method, the population is divided into homogeneous subgroups or strata (in this case, each year level of students), and random samples are then taken from each of these groups to ensure representation from each stratum. Since she is ensuring an equal number of students from each year level by randomly selecting 50 students from each group, this clearly fits the definition of stratified random sampling.