This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Zonula of Zinn is : 
Select and explain. 
A. Primary vitreous, B. Secondary vitreous, C. Persistence vitreous, D. Tertiary Vitreous
D: Tertiary Vitreous
Answer: D: Tertiary Vitreous 
Explanation: The lens is held in position by the suspensory ligament called zonules of Zinn.
A ligament composed of straight fibrils radiating from the ciliary body of the eye to the crystalline lens, holding the lens in place and relaxing by the contraction of the ciliary muscle. - Relaxation of the ligament allows the lens to become more convex.