Since All Action Potentials Are Essentially the Same, How Can

Since all action potentials are essentially the same, how can one differentiate visual and auditory stimuli?

A) The amplitude of each action potential is characteristic of the specific neuron transmitting it to the brain.
B) The length of time each stimulus takes to travel to the brain for interpretation varies.
C) Receptor potentials are graded.
D) Each type of sensory receptor transmits its stimulus to a specific area of the brain for interpretation.
E) The frequency of action potentials is characteristic of the specific neuron.