Final answer:
A gel-based massage medium is the most suitable for oily skin as it doesn't add to the oiliness and is easily absorbed. Oil-in-water lotions could also work but water-in-oil creams might be too heavy.
Step-by-step explanation:
For an individual with oily skin, it is generally recommended to use a gel-based massage medium. A gel-based medium is less likely to add to the oiliness of the skin and can provide a lightweight texture that is easily absorbed without leaving residue. Lotions, particularly those that are oil-in-water emulsions, could also be appropriate as they are less greasy than creams. Creams, especially water-in-oil creams, might be too heavy for oily skin since they provide a barrier that can reduce water loss but might also trap oils and lead to a greasier feel. Selecting a water-based or gel-based medium would be more suitable for managing oily skin during a massage.