Which feature is common to all primates?

A. large brain relative to body size

B. upper body weight distributed over pelvis

C. pelvis rotated inward

D. two arches in foot

The correct option is A.

Primates are a diverse group of animals and they include animals such as apes, monkeys, etc. The primate group is divided into two distinct orders based on the brain size of the animals. Primates have some peculiar characteristics, which include the following: they have shortened snouts, reduced number of teeth compared to other mammals, they possess several types of teeth, which made it possible for them to eat varieties of food and forward facing eyes orbit. Their brains also is large relative to their body size.

"A. large brain relative to body size" would be a feature common to all primates. This is a major reason why primates are considered to be generally smarter than many other animals.