Answer:
A: systematic sampling
Step-by-step explanation:
The correct answer is systematic Sampling.
This is because, Systematic sampling is a method of sampling whereby the researchers choose members of a population at regular intervals e.g., when we select every 10th person on a particular list in the population.
And in this question, the professor starts with the 4th person on the list and selecting every 6th person. Thus, the answer is systematic Sampling.