A punnet square is used to visually see the dominant and recessive traits. Mendel's law says that alleles pair independently during the formation of gametes (aka sex cells). This means that traits are transmitted to offspring independently of one another.
I would say A.
B and C can be eliminated because they have to do with using resources more efficiently. Now we're down to A and D, and of the two, I'd say A is most plausible. Globalization is the connection of the world with each other. With all this technology, companies see endless possibilities to sell their products. They use more and more natural resources, which can deplete those resources quickly.
I believe the answer is Nucleus.