Which of the following correctly explains the use of "tall man" letters?

Tall man letters are used to designate different drug classifications
Tall man letters are used to indicate similarities in drug names
Tall man letters are used to indicate differences in the spelling of drug names
Tall man letters are used only to indicate differences in the spelling of brand name drugs

Tall man letters are used to indicate differences in the spelling of drug names

Rationale: Tall man letters are used to indicate differences in the spelling of drug names. The use of "tall man" (mixed case) letters helps to draw attention to the dissimilarities in their names.