What method should be used to check for responsiveness in an infant?

To check for responsiveness in an infant, the appropriate method is to gently tap the foot and shout. This approach is particularly effective for infants because they are smaller and more vulnerable than older children or adults. Tapping the foot allows for a gentle interaction without causing distress or injury, which is crucial in a situation involving an infant.

Using this method provides not just a way to assess responsiveness but also avoids potential harm. Infants may startle or react negatively to being shaken or having strong, loud stimuli directed at them, which could increase their risk of injury or distress. Therefore, a gentle approach is key, as it helps the rescuer gauge the infant's awareness and responsiveness without overwhelming them.

The other methods listed could result in inappropriate levels of stimulation or physical harm to the infant, making gentle foot tapping the safest and most effective method for checking responsiveness in this age group.