Final answer:
The correct answer is c. Random Sample, which represents a subset of a population where every member has an equal chance of being selected, thereby ensuring a representative sample.
Step-by-step explanation:
A random sample is a sample in which each individual or object in the entire population has an equal chance of being selected. The correct answer to the question is c. Random Sample. Random samples are essential for research because they ensure that the sample is representative of the population. This representative feature is crucial since it allows the percentages of characteristics in the sample, such as sex, ethnicity, socioeconomic level, and more, to closely match those in the larger population. When a random sample is selected, each member has the same probability of being chosen, as is evidenced by random sampling methods like simple random sampling, stratified sampling, cluster sampling, and systematic sampling.