Answer: B) Sample survey
Step-by-step explanation:
When asking/answering questions like this, a survey is involved. It could be multiple choice or fill in the blank. Multiple choice may be the best way because it's easier to compare data results when you have only a few options. It also gives the computer an easier time too.
We aren't conducting an experiment since the researcher is not directly affecting the people, and instead letting them answer the questions without intervention. Also, note how we don't have two groups of treatment vs control. This is another indication we don't have an experiment.
An observational study is not being done here either. Yes the researcher is observing the survey results, but s/he is not making notes on the individuals before the survey is conducted (ie before the questions are asked). An example of an observational study is having the researcher make a tally of students' hair color. The researcher simply looks at each student, marks the correct tally, and doesn't need to ask the student a question. So you can see that the interactive question/answer portion is not present in an observational study.
The phrasing "random trial" is not a study type. When you hear "random trial" in the news, maybe for a new drug being developed, the news report is implying heavily that an experimental study had been done. This is true with all drug trials. One group is the treatment group that gets the actual drug, while the control group gets a fake drug. The control group thinks they get the actual drug, which is important because if they knew it was fake, then it would invalidate the study. I recommend researching the placebo affect for more information. The two group's results are then computed to see if the drug did in fact cause a change in the subjects or not. You would see this if there's a significant difference between the treatment and control group. Anyway, the "random trial" is not a study type but rather an aspect of an experimental study. It's possible your teacher put this in here to throw off students.