4. Which statement describes the relationship between humans' ability to identify animals' grimaces and deciphering other facial expressions?
A The author believes that humans' ability to recognize pain in animals
should lead to the ability to recognize other facial expressions.
B The author discusses how animals' ability to show pain through facial
expression proves that they are capable of a wide range of
expressions.
C That author discusses how humans are only interested in identifying
pained facial expressions in animals to improve the ethical treatment
of them.
D The author explains how a grimace can be used as a base-line
emotion for animals, as all humans and animals have similar
expressions of pain.

I need help now plz