Final answer:
Russ does not have a third nipple on his right foot, left hand, or top of his head. Third nipples, also known as supernumerary nipples, are uncommon and usually occur on the chest area. Option a is correct among the given question.
Step-by-step explanation:
Russ does not have a third nipple on his right foot, left hand, or top of his head. Third nipples are uncommon and usually occur on the chest area, not on the extremities.
They are caused by the development of additional mammary glands during embryonic development. They are actually a type of pigmented birthmark called supernumerary nipples. These extra nipples are caused by the development of additional mammary glands during embryonic development.
Option a is correct among the given question.