Which statement about air pollution in the United Kingdom (UK) is correct?

A.

Historically, air pollution in the UK was caused by construction; today most air pollution comes from factories.

B.

Historically, air pollution in the UK came from factories; today most air pollution comes from automobiles.

C.

Historically, air pollution in the UK came from automobiles; today most air pollution comes from large farms.

D.

Historically, air pollution in the UK came from large farms; today most air pollution is caused by construction.

help please