Karim Is a Law Student, Who Reads an Advertisement for a Sleep-Learning

Karim is a law student, who reads an advertisement for a sleep-learning device that claims to have helped a law student pass the state bar exam. Karim should

A) immediately order this device because the correlation is evidence of the device causing the law student to pass the bar.
B) immediately order this device because a correct inference can be made from this observation.
C) order the device because systematic research has shown that these devices really work.
D) not order the device because an individual case tells nothing about what is true in general.