Which of the following suffixes would indicate a type of "treatment"?

The suffix "-therapy" is specifically used to denote a type of treatment. This term derives from the Greek word "therapeia," which means "to heal" or "to serve." When attached to a root word, it signifies various forms of therapeutic interventions designed to alleviate a condition or improve health. For example, "physiotherapy" refers to physical treatments aimed at managing and healing ailments.

In contrast, the other suffixes represent different concepts. "-tomy" refers to a surgical procedure involving cutting or incisions, such as "appendectomy," which is the removal of the appendix. Meanwhile, "-scopy" indicates the use of an instrument to look inside the body, as seen in "endoscopy." Lastly, "-stomy" denotes the creation of an opening, typically to facilitate the passage of bodily waste, such as in "colostomy." None of these suffixes convey the notion of treatment like "-therapy" does, making it the correct choice for this context.