Over 90 percent of the human brain currently serves no purpose, as is evident from the fact that many people with significant brain damage show no discernible adverse effects. So once humans begin to tap into this tremendous source of creativity and innovation, many problems that today seem insurmountable will be within our ability to solve. Which one of the following most accurately describes a flaw in the argument? ['The argument infers that certain parts of the brain do nothing merely on the basis of the assertion that we do not know what they do.', 'The argument presumes, without providing justification, that the only reason that any problem remains unsolved is a lack of creativity and innovation.', 'The argument infers that problems will be solved merely on the basis of the claim that they will be within our ability to solve.', 'The argument presumes, without providing justification, that the currently unused parts of the brain are a potential source of tremendous creativity and innovation.']