Answer: A. Resting heart rate
Explanation: When your heart rate is at the lowest possible rate, it is called resting heart rate. Resting heart rate refers to the number of times your heart beats per minute when you are at rest, such as when you are sitting or lying down and not exerting any physical effort.
Resting heart rate can vary from person to person and can be influenced by factors such as age, fitness level, and overall health. It is usually measured in the morning after waking up, before any physical activity or caffeine intake.
To measure your resting heart rate, you can locate your pulse on your wrist or neck and count the number of beats you feel in a minute. Alternatively, you can use a heart rate monitor or fitness tracker that can provide you with an accurate reading.
Having a lower resting heart rate is generally considered to be a sign of good cardiovascular fitness. Athletes or individuals who engage in regular exercise tend to have lower resting heart rates because their hearts are more efficient at pumping blood. On the other hand, certain medical conditions or medications may cause an elevated resting heart rate.