If One Impales a Neuron with Two Different Intracellular Microelectrodes

Multiple Choice

If one impales a neuron with two different intracellular microelectrodes, one to measure membrane potential and a second to pass brief hyperpolarizing current pulses into the cell, why does the size of the measured changes in membrane potential caused by the current pulses decrease when transmitter binds to an ionotropic receptor?

A) The ionotropic receptor inhibits a voltage-gated sodium channel.
B) The ionotropic receptor inhibits a voltage-gated potassium channel.
C) The input resistance of the cell does not change when ionotropic receptor channels open.
D) The input resistance of the cell decreases when ionotropic receptor channels open.
E) The input resistance of the cell increases when ionotropic receptor channels open.