This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: Archaeologist Louis Binford criticised the idea that early hominids and early humans were hunters. On the basis of the analysis of the skeletal remains of the consumed animals, he concluded that hominids and early humans were mostly scavengers, not hunters, and this idea is popular among some archaeologists and paleoanthropologists. Robert Blumenschine proposed the idea of confrontational scavenging, which involves challenging and scaring off other predators after they have made a kill, which he suggests could have been the leading method of obtaining protein-rich meat by early humans.
What idea was criticized by Robert Blumenschine?