Final answer:
Piltdown man was a hoax consisting of the lower jawbone of an orangutan and the cranium of a modern human. The deception was eventually uncovered, correcting the scientific understanding of human evolutionary history.
Step-by-step explanation:
The Piltdown man was a paleoanthropological hoax, in which the skull was comprised of the lower jawbone of an orangutan and the cranium of a fully modern human. Thus, the correct answer to which two species made up the Piltdown man is B) a modern human and an orangutan. The Piltdown man was a fraudulent fossil that misled the scientific community about human evolution for a period before it was exposed as a forgery.