The correct answer is (c). Caffeine is a naturally occurring stimulant found in tea leaves, coffee beans, and cocoa beans. It is also added to some soft drinks, energy drinks, and over-the-counter medications. Caffeine is absorbed quickly from the stomach and small intestine and reaches peak levels in the blood within 30 to 60 minutes. It is then metabolized by the liver and excreted in the urine. Caffeine has a half-life of about 5 hours, meaning that it takes about 5 hours for the body to eliminate half of the caffeine that has been consumed.
Caffeine is a central nervous system stimulant that increases alertness, attention, and energy levels. It can also improve mood and cognitive function. However, caffeine can also cause side effects such as anxiety, insomnia, and headaches. In high doses, caffeine can be toxic.
The amount of caffeine in a serving of tea or coffee varies depending on the type of tea or coffee, the brewing method, and the size of the serving. A cup of brewed coffee typically contains about 95 milligrams of caffeine, while a cup of brewed tea typically contains about 47 milligrams of caffeine.
Lemon water does not contain caffeine.