The Secret Triwizard Challenge

The first potion is a foaming, frothy, silvery liquid that sparkles as though containing ground diamonds.
The second potion is a smooth, thick, richly purple drink that gives off a delicious smell of chocolate and plums.
The third potion is a golden liquid so bright that it hurts the eye, and which makes sunspots dance all around the room.
The fourth potion is a mysterious back liquid that gleams like ink, and gives off fumes that make you see strange visions.
You remember the sphinx's words: "Two will help you win your race, only one you need to pick. Two are poison, like stars in space, drink either and die, through thin and thick."
Which potion do you choose to move forward?