Which of the following most logically completes the argument?
A common approach to algae cultivation involves covering a pond with a greenhouse, instead of leaving the pond uncovered. Because there is a practical limit on the size of a greenhouse, this method limits the extent of the algae-growing system. Nevertheless, covering the pond results in a much higher algae yield because.
(A) the greenhouse prevents contamination from invasive bacteria, which can destroy entire species of algae.
(B)
...
A common approach to algae cultivation involves covering a pond with a greenhouse, instead of leaving the pond uncovered. Because there is a practical limit on the size of a greenhouse, this method limits the extent of the algae-growing system. Nevertheless, covering the pond results in a much higher algae yield because.
(A) the greenhouse prevents contamination from invasive bacteria, which can destroy entire species of algae.
(B)
...
