When a research problem is related to a heterogeneous population, the most suitable sampling method is

For a heterogeneous population the most suitable method is stratified sampling.

It divides the population into homogeneous strata and samples from each to capture every subgroup.

Cluster sampling divides the population into geographic clusters and suits scattered, not heterogeneous, populations.

Convenience sampling picks whoever is easily available and cannot ensure representation of a varied population.

The lottery method is a form of simple random sampling and ignores the internal diversity of strata.

Stratified sampling improves precision when strata differ sharply from one another.