Answer:
Potassium permanganate.
Explanation:
Both substances are dyes, but the methylene blue has a bigger molecular mass (319.85 g/mol), that means that the particles are bigger in comparison with the potassium permanganate that has a molecular mass of 158.034 g/mol.
Since the molar mass is the half in the case of potassium permanganate, it can be considered that the particle size is the half in size. In the agar, a smaller particle will present less resistance to flow, that means that it going to move faster.
