The purpose of sampling is to
a. calculate all variables and observations within a population
b. obtain sufficient information to draw a valid inference about a population
c. measure all items of interest for a particular interest or investigation
d. enumerate all the values in the population

b. obtain sufficient information to draw a valid inference about a population

Explanation:

Sampling: In psychological research, the term sampling refers to the group of objects, items, or people that are being taken from a huge population for measurement in a study.

The sample taken from the population should be representative of the given population so that the researcher can generalize or make inference about the findings of the population as a whole.

In the question above, the purpose of sampling is to obtain sufficient information to draw a valid inference about a population.