The correct answer is (d) Kidney.
The kidney is the organ of the body that is affected most on keeping fast for a long time. This is because the kidney is responsible for filtering the blood and removing waste products from the body. When you fast, your body goes into a state of ketosis, which means that it starts to break down fat for energy. This process produces ketones, which are waste products that the kidney has to filter out of the blood. If you fast for a long time, your kidneys can become overloaded with ketones, which can lead to kidney damage.
The other options are incorrect because they are not the organs that are most affected by fasting. The heart is responsible for pumping blood throughout the body. The intestine is responsible for digesting food and absorbing nutrients. The lung is responsible for breathing and exchanging oxygen and carbon dioxide.
It is important to note that fasting can be a safe and healthy way to lose weight or improve your health. However, it is important to talk to your doctor before starting any fasting regimen, especially if you have any underlying health conditions.