Which of the following material is used for preserving semen?

The material used for preserving semen is Egg yolk.
Egg yolk is a common additive to sperm cryopreservation diluents. Because of its animal origin, however, it also represents a potential risk of microbiological contamination in the diluent.
Egg yolk is the primary non-penetrate substance used in extenders to dilute semen and protect sperm from freeze shock during the chilling process. Egg yolk-based extender is commonly used in chilled, frozen semen, or both.