Final answer:
To determine whether a bloodstain is of human or animal origin, the forensic scientist will perform a hexagon OBTI test. Option a is correct.
Step-by-step explanation:
The hexagon OBTI (Ovulation and Bloody Trace Identifier) is a rapid immunoassay designed to specifically detect human hemoglobin in blood traces. This assay is based on the recognition of human hemoglobin by monoclonal antibodies that are used on a test strip.
Other tests such as luminol or bluestar can detect blood presence but are not species-specific. Analysis with hemastix, strips antigens, and acid phosphatase tests are other types of blood tests, but they are not the primary choice for species determination in forensics.
Tests like ELISA (enzyme-linked immunosorbent assay) and lateral flow assays also use antibodies and antigen interactions for detecting specific biological molecules. These methods are useful in medical diagnostics and have some principles in common with forensic tests like the hexagon OBTI test.