Nowadays, molecular pieces of evidence are used to show the similarity between two species as the universal molecule- DNA is present in all living organism from lower to higher organisms which code for the amino acids of the proteins.
The differences and similarities between genomes of two different species confirm relatedness as a mutation in genes can show evolutionary patterns which can be summarized as:
differences between base sequences can show the degree of divergence.
a large number of differences means species diverged long ago.
more similarity in sequence means species are more closely related.
Thus, molecular evidence is used to show species relatedness.
The best answer to the question that is being presented above would be letter a. The poplar trees used by the company and its factories which are genetically engineered would be used for phytoremediation. They use poplar trees to replenish the nutrients lost around the factories.