The correct answer is option 2, ear muscles. A vestigial organ is an organ that has lost its original function over the course of evolution. In the case of ear muscles in humans, they are vestigial because they were once functional in our evolutionary ancestors but no longer serve any purpose in the human body.

Option 1, jaw apparatus, is not a vestigial organ as it is still fully functional and necessary for eating and speaking.

Option 3, canine teeth, are not considered vestigial organs either. Canine teeth serve a purpose in humans for biting and tearing food.

Option 4, humerus, is the bone in the upper arm and is not considered a vestigial organ. The humerus is essential for the functioning of the human arm and is still fully functional.

It`s important to note that the presence of vestigial organs in different species can vary, so while ear muscles may be vestigial in humans, they may still serve a purpose in other animals.