Lead II measures the electricity between RA and LA in an inferior direction.
In an electrocardiogram (ECG), lead II measures the electrical activity between the right arm (RA) and the left arm (LA) in an inferior direction.
Lead II is obtained by connecting the positive electrode to the right arm (RA) and the negative electrode to the left arm (LA). It provides a specific view of the heart's electrical activity from the right shoulder to the left leg.
Therefore, the correct answer is d. Lead II.