The correct answer is D. (a) and (c) both of them.
A probability sample is a sample in which every member of the population has a known and equal chance of being selected. Quota sampling and purposive sampling are both non-probability samples.
In quota sampling, the researcher sets quotas for different groups in the population and then selects participants until the quotas are filled. This type of sampling can be useful when the researcher wants to ensure that the sample is representative of the population on certain characteristics. However, it is not a random sample, so the results may not be generalizable to the population as a whole.
In purposive sampling, the researcher selects participants based on their knowledge or experience with the topic being studied. This type of sampling can be useful when the researcher wants to gain in-depth information from a small number of participants. However, it is not a random sample, so the results may not be generalizable to the population as a whole.
Here is a table that summarizes the key differences between probability and non-probability samples:
| Probability sample | Non-probability sample |
| — | — |
| Every member of the population has a known and equal chance of being selected | Members of the population are not selected randomly |
| The results are generalizable to the population as a whole | The results may not be generalizable to the population as a whole |
| Useful for estimating population parameters | Useful for gaining in-depth information from a small number of participants |
I hope this helps! Let me know if you have any other questions.