The adjective "trabajador" is masculine and singular. It also has a plural form, "trabajadores." Thus, we will look for nouns that are both masculine and can be singular or plural depending on the context.
The nouns that agree grammatically with "trabajador" are:
- los hombres (plural, masculine)
- el profesor (singular, masculine)
- mi tío (singular, masculine)
So the correct selections are:
- los hombres
- el profesor
- mi tío