Final answer:
In 1863, Thomas Huxley proposed that humans are related to chimpanzees and gorillas. We know now that humans and chimpanzees are more closely related than either is to gorillas.
Step-by-step explanation:
In 1863, Thomas Huxley proposed that humans are related to chimpanzees and gorillas. We now know that humans and chimpanzees share a more recent common ancestor than either does with gorillas. Therefore, the correct response is choice 3) Chimps.
Gibbons, as mentioned in the article, belong to the family Hylobatidae, not Hominidae, and are not closely related to humans. Therefore, choice A) Gibbons is incorrect.
Gorillas are indeed related to humans, but they are not our closest relatives. Humans share a more recent common ancestor with chimps, making choice C) Chimps the correct response.