Which of the following substances is known as a club/date rape drug?

The substance recognized as a club or date rape drug in this context is GHB (gamma-hydroxybutyric acid). GHB is known for its psychoactive properties and is often associated with instances of drug-facilitated sexual assault due to its ability to cause sedation and amnesia. It can be odorless and colorless, making it easier to be surreptitiously added to drinks without the victim's knowledge.

While benzodiazepines can also be misused in similar contexts, GHB is specifically categorized as a club drug because of its common use in nightlife settings and its association with non-consensual drug use. The other options—caffeine and aspirin—do not possess the same dangerous effects related to sedation and incapacitation that are characteristic of GHB and benzodiazepines. Thus, GHB is the most recognized of these substances in relation to the term "club/date rape drug."