You Meet a Young Lady Who Giggles After Every Sentence

You meet a young lady who giggles after every sentence she says.You conclude that she is a very happy person,but you later find that her giggling is due to nervousness in meeting new
People.This story suggests that it is important to distinguish between

A) individual cases and generalizations.
B) correlation and causation.
C) control groups and experimental groups.
D) observation and inference.