Final answer:
Livor mortis is the discoloration that can usually be removed by venous drainage. It occurs after death as blood settles in the lower parts of the body and can be shifted if the body is moved shortly after death.
Step-by-step explanation:
The discoloration that can usually be removed by venous drainage is c. Livor mortis.
Livor mortis, also known as postmortem hypostasis, is the purple or red discoloration that appears on the dependent parts of the body following death. This occurs due to the settling of blood within the vasculature under gravity's influence. Because livor mortis results from blood pooling, it can be altered or shifted when pressure is applied, or if the body's position is changed within the first few hours after death. Venous drainage or relocation of the body can diminish the appearance of livor mortis which suggests that it is not yet fixed. Other types of discoloration like jaundice, resulting from excess bilirubin due to liver dysfunctions, postmortem stain from the breakdown pigments formed from hemoglobin, and discoloration due to hemolysis are generally not reversible with venous drainage.