Final answer:
The correct answer is A. Stratified sampling. Stratified sampling involves dividing the population into distinct groups or strata, and selecting a proportionate number of individuals from each stratum to form the sample.
Step-by-step explanation:
The correct answer is A. Stratified sampling.
Stratified sampling involves dividing the population into distinct groups or strata, and then selecting a proportionate number of individuals from each stratum to form the sample. In this case, the instructor selects five students from each math class, which represents the use of stratified sampling.
For the other options:
- A. Cluster sampling involves dividing the population into clusters and selecting entire clusters at random. Each math class is not considered a cluster.
- B. Convenience sampling involves choosing individuals who are readily available. The instructor did not choose the students based on convenience.
Therefore, the correct answer is A. Stratified sampling.