which of the following is true of research on insight?

Which of the following is true of research on insight?

A) Researchers have found support for the existence of both human and animal insight learning.

B) Researchers have found that apes are capable of insight only after being taught this by humans.

C) Researchers have proven that all creatures, even one-celled organisms such as the amoeba, are capable of insight learning.

D) Researchers have found that only human beings are capable of insight learning.