Some researchers have noted that adolescents who spend a lot of time watching horror movies are at greater risk of depression and violence. This is an example of a(n):
A. valid conclusion because more time yields more aggression is a positive association.
B. observational study with lurking variables that may explain the association.
C. single-blind experiment because the subjects knew they were watching television.
D. paired data experiment because we are studying both aggression and TV watching.
I chose D is that correct?