GMAT Critical Reasoning (CR) | Re: Naturally occurring vitamins : Weaken

Keats , we absolutely have to accept the truth of the answers. So it's true that nutritionists prescribe vitamins. However, we have no idea aboutwhy , let alone whether that reasoning is correct. (Perhaps the nutritionists are mistaken, or perhaps they know that vitamins don't work and prescribe them anyway.) Similarly, if a choice said "Jay believes in ghosts," then we'd grant that Jay believes in ghosts. We believe that he believes in them. That doesn't mean that ghosts are real!