Final answer:
The green lead for a Holter monitor should be placed on the right leg.
Step-by-step explanation:
When applying electrodes for a Holter monitor, the green lead is typically placed on the right leg. This is one of the four electrodes placed on the limbs. In a 12-lead ECG, six electrodes are placed on the chest and four electrodes are placed on the limbs. The green lead should be placed on the right leg because it helps to complete the electrical circuit and provides a reference point for recording heart activity.