A dilator is primarily used for which of the following purposes?

A dilator is primarily utilized for the purpose of stretching or widening an opening in the body, making option C the correct choice. Dilators are surgical instruments designed to gradually expand or enlarge an opening, such as a blood vessel, duct, or other anatomical structures, to facilitate access or allow for the insertion of other instruments or devices.

The mechanism of a dilator involves inserting it into a tight or constricted space and gently widening that space, thereby ensuring better access for surgical procedures or interventions. This is critical in various surgical contexts, such as during the placement of stents, in certain gynecological procedures, or when preparing an area for other surgical activities.

Options that imply cutting tissue, separating tissues, or fixating tissue do not properly characterize the primary function of a dilator. Surgical instruments designed for cutting or separating tissues have different specific designs and mechanisms suited to those tasks, while fixation instruments are intended to hold tissues in place rather than expand openings.