Mark the letter A, B, C, or D to indicate the correct response to each of the following exchanges. Two friends Nam and Lan are talking about the topic of global warming.
Lan: What solution to air pollution can you suggest? - Nam: ____
A. Air pollution is really serious these days.
B. Smoke from factory chimneys pollutes the air.
C. Air pollution causes acid rain.
D. People should use public means of transport.