Final answer:
The temporalis muscles facilitate the function of mastication, which is the process of chewing, by helping to retract the mandible and elevate and close the jaw. Option d is correct.
Step-by-step explanation:
The temporalis muscles are involved in the action of mastication, which is the process of chewing. These muscles, along with the masseter muscles, are responsible for elevating and closing the jaw to break food into digestible pieces.
The temporalis muscles specifically help to retract the mandible, a movement that is crucial for the proper functioning of the temporomandibular joint (TMJ), allowing for the opening and closing of the mouth during the act of chewing. Based on the options provided, the correct function facilitated by the temporalis muscles is d. Mastication.