What Did Alan Hodgkin and Andrew Huxley Conclude from Their

What did Alan Hodgkin and Andrew Huxley conclude from their squid axon experiments?

A) The passage of Na⁺ ions into a neuron and K⁺ ions out of a neuron results in an action potential.
B) The passage of K⁺ ions into a neuron and Na⁺ ions out of a neuron results in an action potential.
C) The passage of K⁺ ions into a neuron and Ca⁺ ions out of a neuron results in an action potential.
D) The passage of Cl^- ions into a neuron and K⁺ ions out of a neuron results in an action potential.
E) The passage of Cl^- ions into a neuron and Ca⁺ ions out of a neuron results in an action potential.