ANSWER: Option B
Explanation:
When John hits the mat, the impact on his head which cause rapid impact and due to this it disturbs the blood flow in a particular area.
A large amount of nerve cells present at the back of the head can also be affected due to hit. This rapid impact results in seeing stars because the occipital lobe is the location where the visual cortex is present.
hence, the correct answer is option b. Occipital lobe.