East Asians Who Have Migrated Recently from India and Pakistan

East Asians who have migrated recently from India and Pakistan to northern areas of the United Kingdom have a higher incidence of rickets and osteoporosis than the general British population. This illustrates that

A) natural selection's role in determining skin color is a thing of the past, relevant only prior to the sixteenth century when massive migrations of populations altered the geographic distribution of dark-skinned people.
B) natural selection continues today.
C) because of global warming, the lack of sunlight that people are exposed to in these northern regions is made up for by the intensity of the sunlight.
D) genetic adaptation of environmental stressors can occur within one generation.
E) cultural adaptation provides effective shortcuts to the genetically disadvantaged in a foreign environment.