For PV systems, a(n) _____ is a device that changes direct-current input to an alternating-current output.
See answer and applicable Code reference
The correct answer is: d) inverter
The provisions of Art. 690 apply to solar PV electrical energy systems. As noted in the definitions Section [690.2], an inverter is defined as: "Equipment that is used to change voltage level or waveform, or both, of electrical energy. Commonly, an inverter [also known as a power conditioning unit (PCU) or power conversion system (PCS)] is a device that changes DC input to an AC output. Inverters may also function as battery chargers that use alternating current from another source and convert it into direct current for charging batteries."