An inhibitory postsynaptic potential (IPSP) can result from the ________.

A) influx of Ca²⁺
B) influx of Na⁺
C) influx of Cl⁻
D) outflow of K⁺
E) Both "influx of Cl⁻ and "outflow of K⁺" are correct.

Inhibitory postsynaptic potentials (IPSPs) are typically caused by the influx of chloride ions (Cl-) or the outflow of potassium ions (K+), both of which make the inside of the cell more negative and thus less likely to fire an action potential.