Answer:
The answer is convenience sampling.
Explanation:
As per the given scenario, the president of the math club is conducting a survey to see where the twelfth-grade class wants to go on their field trip and she surveys only the twelfth-grade members of the math club.
This is convenience sampling as here the samples are the closest people available. Convenience sampling is a method where the samples are taken who are close to hand.
Here also the math club president is asking the math club students only. This is why it is convenience sampling.