A person who is "speedballing" is?

The correct answer focuses on the specific practice known as "speedballing," which refers to the concurrent use of cocaine and heroin. This combination of a stimulant (cocaine) and a depressant (heroin) can lead to intense highs from both drugs. Users may seek the euphoric effects of cocaine while trying to attenuate the intense crash and withdrawal symptoms that cocaine can cause with the sedative effects of heroin.

This practice is particularly dangerous because the contrasting effects of the two substances can lead to increased risk of overdose. Users might not realize how much of each drug they are consuming, as the stimulation from cocaine can mask the depressant effects of heroin, potentially leading them to take more than their body can handle.

Other choices are less accurate as they either describe conditions related to drug use rather than the specific act of speedballing or refer to methods of drug packaging and withdrawal behaviors that do not capture the essence of what speedballing entails.