To determine customer opinion of their pricing, greyhound lines randomly selects 90 busses during a certain week and surveys all passengers on the busses. what type of sampling is used?

Cluster sampling.

Step-by-step explanation:

Cluster sampling is a sampling technique in statistics in which the  researcher splits the entire population into different groups called clusters.After that he randomly select a sample from the clusters from the population and survey all elements of sampled clusters.Researcher performs his analysis on data from the sampled clusters.

In the given situation Greyhound Lines randomly selects 90 buses during a certain week and surveys all passengers on the buses.

Here, week= Cluster

Buses = Elements

Therefore , the type of sampling is used = Cluster sampling.

The answer to that is 6