Researchers have discovered that caffeine can be as physically addictive as other psychoactive substances. Some people find that they become unusually depressed, drowsy, or even irritable if they do not have their customary dose of caffeine. This is significant because as many people consume caffeine as consume any one of the other addictive psychoactive substances. Which one of the following can be logically concluded from the information above? ['Not all substances to which people can become physically addicted are psychoactive.', 'If one is physically addicted to a psychoactive substance, one will become unusually depressed when one is no longer ingesting that substance.', 'If alcohol is a physically addictive psychoactive substance, there are not more people who consume alcohol than consume caffeine.', 'There is no psychoactive substance to which more people are physically addicted than are addicted to caffeine.']