Final answer:
The correct statement about the use of the deltoid muscle site in parenteral administration is that it is used for administering the hepatitis B vaccine; it is not ideal for large volume or irritating medications.
Step-by-step explanation:
The statement that is true regarding the use of the deltoid muscle site in parenteral administration is that the deltoid muscle site is used to administer the hepatitis B vaccine. The deltoid is a large, triangular-shaped muscle that covers the shoulder, suitable for the administration of small to moderate volume injections, such as vaccines. It is not typically used for medications that have large volumes or are viscous and irritating, as these characteristics would be more appropriate for sites that can accommodate larger volumes or have thicker muscle tissue such as the ventrogluteal site.