A.
I say this because there are other ways to make DNA in plant cells like adenine, cytosine, guanine, and thymine so B is out. Though, Mitochondria does break down waste so part of B is right but that would cancel out C. Without Chloroplasts, a plant cannot make food so D is out as well. Hope this helped!
Answer:
NADH
Explanation:
Electron carriers such as NADH produced during glycolysis and the Krebs cycle pass their electrons to the electron transport chain, which results in synthesis of a lot of ATP.
Atoms that are unstable undergo radioactive decay,
Elements with half life(that's how we know that it decayed),
Atoms that release energy and particles(like alpha beta and gamma particles) and,
Elements that have turned into a new element (as in radioactive decay no. of protons can decrease)
And to be precise the elements that have neutron to proton ratio of more than 1 undergo radioactive decay, since the nuclear attraction gets all weird after that.