The correct option is (d) smart pad
The explanation: Smart pad is a system that displays patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer.