Robin Dunbar Argues That Conversational Language Emerged in Human Beings

Robin Dunbar argues that conversational language emerged in human beings because:

A) Human groups became too large for grooming to be a practical way of maintaining social bonds; therefore, conversation developed as a necessary replacement for grooming.
B) Human beings naturally imitated noises in their environment, and these noises became words.
C) Humans developed tongue movements to mimic manual gestures, something that helped with the acquisition of increasingly sophisticated manual habits.
D) Humans needed words to help mediate conflicts within the group.