Which from following compounds is classified as oligosaccharide?

Carbohydrates that yield two to ten monosaccharide units on hydrolysis are called oligosaccharides.

Sucrose is a disaccharide, which is a type of oligosaccharide, as it yields one molecule of glucose and one molecule of fructose on hydrolysis.

Ribose, fructose, and glucose are monosaccharides, as they cannot be hydrolyzed further into simpler units of polyhydroxy aldehydes or ketones.