Explanation:
A normal blood pressure level is less than 120/80 mmHg. No matter your age, you can take steps each day to keep your blood pressure in a healthy range.
Given the attitude of the grandfather portrayed in the problem, the most likely answer is
B) Go to the doctor regularly because he can monitor his health before problems get severe.
This would be because you are reminded, "prevention is the best medicine", and the answer B provides the precaution that is recommended.
I think that oxygen is needed , because it helps elevate the blood level and help oxygen spread to your brain/ heart.
I need more information please then I would be glad to help!