**Core Concept**
Vicryl is a type of synthetic suture material, specifically a polyglactin 910 absorbable suture. It is widely used in surgical procedures due to its unique properties, which allow for a balance between strength and biodegradability.

**Why the Correct Answer is Right**
Vicryl is a type of polyglactin suture, which is made from a copolymer of lactic acid and glycolic acid. This unique composition allows Vicryl to be absorbed by the body over time, reducing the risk of chronic foreign body reactions. The degradation of Vicryl occurs through hydrolysis, where water molecules break down the ester bonds between the lactic and glycolic acid units, resulting in the formation of carbon dioxide and water.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Vicryl is not a type of nylon suture, which is a different class of synthetic suture materials.
**Option B:** This option is incorrect because Vicryl is not a type of steel suture, which is a type of non-absorbable suture material.
**Option C:** This option is incorrect because Vicryl is not a type of collagen suture, which is a type of biologic suture material derived from animal sources.

**Clinical Pearl / High-Yield Fact**
It's essential to note that Vicryl has a specific degradation time frame, typically ranging from 60 to 90 days, after which it is fully absorbed by the body. This information is crucial for surgeons to plan post-operative care and follow-up appointments.

**Correct Answer: D. Polyglactin 910 absorbable suture.**