The correct answer is: C. The population was homogenous.
A homogenous population is one that is uniform or consistent in its characteristics. This means that the members of the population are all very similar to each other. When a researcher selects a sample from a homogenous population, the sample is likely to be representative of the population as a whole. This is because the members of the sample are all very similar to the members of the population.
If the population is not homogenous, then the sample may not be representative of the population as a whole. This is because the members of the sample may not be similar to the members of the population. For example, if the population is made up of people of different ages, then a sample of only young people may not be representative of the population as a whole.
In the case of the researcher who selects only 10 members from the total population of 50,000 as a sample, his research can be considered to be good if the population is homogenous. This is because the sample is likely to be representative of the population as a whole. However, if the population is not homogenous, then the sample may not be representative of the population as a whole.
The other options are not correct. A researcher can be a good researcher even if he does not select a homogenous sample. A researcher can also be guided by his superior and still select a non-representative sample. Finally, a population can be considered to be homogenous even if the researcher does not select a representative sample.