The correct answer is (d) Amperometric biosensor
To explain: Amperometric biosensor function by the production of a current when a potential is applied between two electrodes. They generally have response times, dynamic ranges and sensitivities similar to the potentiometric biosensors, which makes use of ion-selective electrodes in order to transduce the biological reaction into an electrical signal. Optical biosensors involve determining changes in light absorption between the reactants and products of a reaction or measuring the light output. Calorimetric biosensor involves measuring the heat generated during a reaction using thermistors.