Answer:
b.representative of the population.
Step-by-step explanation:
A sample is a collection of small quantity or part which is normally taken from a large mass of quantity that represents the whole having the same characteristics.
A sample should be a representative of the entire population in consideration to make sure to generalize the results from the sample of the research to the population as a whole. A sample is a subset of the population and is considered as the best sample when it represents the whole population.
Hence the correct option is (b).