What effect do central nervous system (CNS) stimulants have on a person?

Central nervous system stimulants primarily function by enhancing the activity of certain neurotransmitters in the brain, which leads to noticeable increases in alertness, attention, and energy levels. Users often report feeling more confident and capable of focusing on tasks, as stimulants can improve cognitive functions and reduce the perception of fatigue. This heightened state of alertness and improved mood can make activities feel easier and more manageable, which is why this option accurately reflects the physiological and psychological effects of CNS stimulants.

In contrast, the other options describe effects that are contrary to what CNS stimulants do. Decreased heart rate and energy levels would typically be associated with depressants rather than stimulants. Induced drowsiness and lethargy further align with depressant effects, which counter the stimulating properties. Lastly, while enhanced ability to care for others might imply increased energy, it is not a primary or clear effect of CNS stimulants, as the focal impact is more on personal alertness and cognitive enhancement.