B, the others are not testable under lab conditions.
I think it is A because they can just destroy it but D is finding something natural to kill it off but it is GM so it wouldn't help so A
Explanation:
Plants use photosynthesis to capture carbon dioxide and then release half of it into the atmosphere through respiration. Plants also release oxygen into the atmosphere through photosynthesis.
if my answer helps you than mark me as brainliest
Vector: anything that transmits a disease.
Malaria vectors can include mosquitos, ticks, and other blood sucking insects.
P.S.: Hope I Helped :)