Final answer:
The deep inguinal ring is a small opening in the abdominal wall, serving as the entrance to the inguinal canal, and is relevant in the passage of structures like the spermatic cord or the round ligament.
Step-by-step explanation:
The deep inguinal ring is C) A small opening in the abdominal wall. It is an anatomical structure formed by the transversalis fascia in the inguinal region and represents an elongated basin or groove through which structures such as the spermatic cord in men and the round ligament in women pass. The deep inguinal ring serves as the entrance to the inguinal canal, which is an important passage running parallel to the inguinal ligament.
The deep inguinal ring is not directly related to bone, so it does not match descriptions such as a slit through bone or a hole through bone. Instead, it is more accurately described in terms of a gap within the connective tissue of the abdominal wall.