A blocking _____ is used to block reverse current flow into a PV source circuit.
d) all of the above
See answer and applicable Code reference
The correct answer is: c) diode
The provisions of Art. 690 apply to solar photovoltaic (PV) electrical energy systems, including the array circuit(s), inverter(s), and controller(s) for such systems. As noted in the definitions section of this Article, a blocking diode "is used to block reverse flow of current into a photovoltaic source circuit."