Multi-select problem: How does the next paragraph end?

How to choose solar panels
Choose monocrystalline solar panels for efficiency.
Monocrystalline solar panels are the best at converting light to energy because of their high silicon purity. That being said, monocrystalline solar panels are often the most expensive-this option is best if you want the highest productivity and price tag.

Available choices:
[a]. Monocrystalline solar panels usually come in 2 levels. The first setting allows for solar panels to convert temperature into energy..
[b]. These panels do not cost very much and also should be relatively inexpensive. Work with manufacturers to find the best eco-friendly material for your solar panels..
[c]. Monocrystalline solar panels cost between $300-700 usd per panel. Monocrystalline solar panels also produce the most waste when they're manufactured..
[d]. Purchase solar panels if you want one year to use these solar panels. You can purchase solar panels from big box stores like target, barnes & noble, and electronics stores..
[c].