Answer: a. Convenience sampling
Explanation:
Convenience Sampling is a sampling method that involves the selection of a group of people based on how easy it is to reach them.
With Convenience Sampling, the goal is essentially to conduct research on people you can get to easily. Social media polls are an example of Convenience Sampling as well as walking around in malls and gathering data from people.
By requesting that customers who were already in the hotel, participate in the research, the Tourist Resort is using the Convenience Sampling method as it's prospective participants are in the vicinity and easy to reach.