The best sample is one that is a systematic sample.

a. convenient.
b. representative of the population.
c. purposefully selected.
d. none of the above.

b.representative of the population.  

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).

well its not not rising unemployment and falling inflation.

hope this good !

well it depends i think people around the world are coming around to gay marriage. but if you are talking abortion then wow, so much to talk about. such as men thinking they have the right to choose if women can, the fact there are health concerns if the women can't get one, and many more arguments to discuss. so i would definitely say abortion would be a much more interesting topic.