Answer:
Convenience sampling
Explanation:
From the question, we understand that 40 of all students are to be surveyed. This implies that from the 41st till the last student will not be a part of the survey.
When sampling is done, taking a part of the whole population that is near or readily available; such sampling is referred to as convenience sampling.
The whole population, in this case are all students while the convenience being selected are the first 40 students.