Which statement identifies the function of a cathode in every electrochemical cell?

A. Electrons are lost from the cathode

B. Reduction occurs at the cathode.

C. Positive ions flow away from the cathode.

D. The oxidation number increases at the cathode.

B. Reduction occurs at the cathode.

Step-by-step explanation:

That's the definition: The cathode is the electrode at which reduction occurs.

A is wrong. The cathode gains electrons through the external circuit.

C is wrong. The cathode has the electrons, so cations move toward it.

D is wrong. Reduction occurs at the cathode, so the oxidation number decreases.