I believe that Simple Random Sampling where every element has an equal chance of getting selected to be the part sample is suitable. You may also use the convenience sampling where the samples are selected based on the availability of elements.

Simple Random is the best

regards

Thank you Mahfuz Judeh , Hassan Nima & Ismail W. R. Taifa for your feedback.

A friend of mine suggested stratified random sampling in which the population are the university students while the strata would be the bachelor degree students from these universities. Would this sampling technique be applicable?

Perhaps stratified random sampling will be better than simple random sampling as suggested by Fairuz Hidayat Merican Wan Merican . In this case, each university will serve as a stratum or subgroup from which equal number of bachelor students will be selected from. If simple random sampling is used and all the students from the all the universities are lumped together, there may be a possibility of selecting far too many sample students from a university than another which may not be true representatives of the entire population. Should the respondents have to be selected from only one university, simple random sampling will be okay baring other conditions.

If you can get the number of students in each university, it means that your research community is specific. Therefore, each university can be considered a stratum so, stratified random sampling is best.