
Answer:
B. A precipitin test is the correct answer
Explanation:
To determine whether a bloodstain is of human or animal origin, the serologist will perform: A precipitin test.
The precipitin test is based on the interaction between antigen and antibody which results in the formation of antigen-antibody complexes and this visible precipitate antigen-antibody complexes is called precipitin.
Precipitin test is a serological test where antibody reacts with soluble antigen to produce a precipitate.
The precipitin test is used to distinguished whether the blood sample is from human or different sources.