9. why do solar cells need an inverter? explain.

a. their energy output is alternating current.
b. they need a way to store energy for cloudy days.
c. they need a way to share their excess energy with the electric company.
d. their energy output is direct current.

The energy output is in form of alternating current which gets converted from direct current through inverter.

Option A

Explanation:

When solar collectors collect sunlight and convert it into energy, they are sent to a inverter that can direct the energy and converts it into alternating energy. Then you can power your devices and electronic equipment by solar cells.

Converting the constant power of solar modules into alternating current is the main function of the inverter. Various electrical components are connected to the circuit that can assist in conversion. Basically, the performance of a solar system is used to power AC consumers.  

i'm sure the answer you are looking for would be

a. an ice age

hope this contact me if this didn't or you need with more answers : )

a. i. only is correct.