Read the following advertisement / email and mark the letter A, B, C, or D to indicate the correct option that best…

Read the following advertisement / email and mark the letter A, B, C, or D to indicate the correct option that best fits the numbered blanks.

The Health Environment Management Agency proposed that kindergarteners and primary school students may stay home (1) ________ air quality indexes are hazardous for three days straight. The proposal was (2) ________ because poor air quality in some areas has hurt people's health.

Last week, Hanoi's air quality often reached hazardous levels, (3) ________ of respiratory diseases, strokes, and cancer. Health experts say (4) ________ contact with air pollutants can also cause skin damage and affect the immune system. People should know (5) ________ to avoid outdoor activities and wait until it clears up. They should also know how to close doors and windows properly to avoid pollutants.

Experts say air pollution has been a problem for years in Vietnam, (6) ________ in major cities like Hanoi, partly due to poor management of emission sources from vehicles, construction sites, and industrial facilities.

(Adapted from VnExpress International)