Final answer:
The payback period for the equipment purchase is 5 years, which is the time it takes to recoup the investment cost through the panel's output energy.
The correct option is a) 5 years
Step-by-step explanation:
The question asks to determine the payback period for an equipment purchase. The payback period is the time required to recoup the investment cost through the generated savings or revenue. In the provided context, it mentions that it takes 5 years of the panel's output energy to fabricate the panel. This implies that the equipment purchase will have its investment cost returned or paid back over a period of 5 years.