Answer:
D. stratified random sampling
Step-by-step explanation:
In this example, the employment agency is dividing the population that it will study into different subgroups (age, gender, graduates, nongraduates, and discipline of graduation). These subgroups are known as strata. Afterwards, the agency selects sample members of each of these subgroups. As the samples are chosen on a proportional way based on subgroups, this is known as stratified random sampling.