Doc Robbins: The answer is, the three main ways to take cocaine.
Grissom: Alright, Alex... What is snorting it, smoking it, or injecting it.
Doc Robbins: Very good. The answer is, normal nasal passages, clear lungs, and no track marks on the body.
Grissom: Continuing this childish metaphor... What is how did the drugs get into his system?
Doc Robbins: We'll have to wait for Final Jeopardy.
This is a reference to the popular game show
Jeopardy. The game show includes three rounds, and the last round is called Final Jeopardy.