Step 1. Simplify brackets

Step 2. Simplify
13
Done! :)
Your answer is A. 13 Hope this helps!
The signs and symptoms of a cluster headache include severe<span> right-sided headache with a runny nose, droopy eyelids, and tearing of the eye on the right side.
</span>The injectable form of sumatriptan<span> (</span>Imitrex<span>), which is commonly used to treat a migraine, is also an effective treatment for acute cluster headache</span>
Answer:
D
Explanation:
With a higher surface area the cell is able to produce more ATP