Answer: Your friends’ conclusion would be an example of a(n): d.observation
Step-by-step explanation:
An observation occurs when a person or people embark on a mission to carefully observe someone or something , watching that person's every step and action. They notice , the fact that they notice is an indication that they have been watching this girl and others who text under their desks.
When an observation has been made the observer is able to say something about that person or something that they have been observing due to the fact that they have watched their behaviour. The friends are able to conclude and say the professor has had it "out for this students"they making this conclusion after what they have observed from this other students.