The correct answer is A: Very low. The typical output impedance of an operational amplifier (op-amp) is very low, typically in the range of a few ohms to tens of ohms. This low output impedance is a key characteristic of op-amps that makes them useful as voltage sources. Op-amps are designed to have very low output impedance so they can drive loads without significant voltage drop. The low output impedance means the op-amp can supply current to a load while maintaining a relatively constant output voltage. This is essential for op-amp applications like voltage followers, buffers, and amplifiers where you need a stable output voltage regardless of the load. The very low output impedance (often less than 100 ohms) contrasts with the very high input impedance (typically megohms) of op-amps.