The correct option is D Dihydroxyacetone
Trioses are sugar molecules with three carbon atoms. They can be either aldose or sugar with an aldehyde group (aldotriose) or a ketose sugar with a ketone group (ketotriose). Glyceraldehyde is an example of aldotriose while dihydroxyacetone is a ketotriose.
Erythrulose is a ketotetrose or a sugar with 4 carbon atoms and ketone group. Ribulose is a ketopentose or a 5-C sugar with a ketone group.