The correct answer is a) artificial selection.
Broccoli, cabbage, and brussels sprouts are varieties of the same species, Brassica oleracea, which is a species of wild mustard. These varieties were developed by humans through a process called artificial selection, which is the process of selecting and breeding plants or animals with desired traits through human intervention. This process can lead to the development of new varieties or breeds of plants or animals that have specific characteristics that are not found in their wild ancestors.
In contrast, natural selection is a process that occurs in nature and involves the survival and reproduction of individuals with traits that are better suited to their environment. Genetic drift is a random process that can lead to changes in the frequency of certain genes in a population over time. Inheritance of acquired characteristics is a concept that was proposed by Jean-Baptiste Lamarck in the early 19th century, but it has been largely rejected by modern science because it is not supported by evidence.