Answer: (B) stratified random sampling.
Step-by-step explanation:
Here, Math department can send 6 people to a national convention and they would like to send 4 students out of 30 and 2 faculty members out of 6.
The department is considering both groups or strata of Students and faculty members as well.
And they selected 4 students randomly out of 30, and then 2 faculty members are randomly selected from the six.
Therefore , This is an example of stratified random sampling.
Hence, the correct option is (B) stratified random sampling.