The correct answer is A. 4 mA.
The human body is a conductor of electricity, and when a current passes through it, it can cause a variety of effects, depending on the amount of current and the path it takes. A small current, such as 4 mA, can cause a tingling sensation, but it is not likely to cause any serious harm. A larger current, such as 9 mA, can cause muscle contractions and a loss of control over the muscles. A current of 15 mA or more can cause ventricular fibrillation, which is a condition in which the heart beats irregularly and can lead to death.
The amount of current that is safe for the human body to carry depends on a number of factors, including the path of the current, the duration of the current, and the individual’s health. In general, however, a current of 4 mA or less is considered to be safe for most people.
Option B, 9 mA, is a higher current than is considered safe for most people. Option C, 15 mA, is a very high current that can cause serious harm or death. Option D, 25 mA, is an extremely high current that is almost certain to cause death.