Engine exhaust, industry, domestic heating, and volcanic eruptions are all sources of:

i think the answer is c

hope this

low context culture   (lc.):

association:    

relationships begin and end quickly. many people can be inside one's circle; circle's boundary is not clear.

things get done by following procedures and paying attention to the goal.

one's identity is rooted in oneself and one's accomplishments.

social structure is decentralized; responsibility goes further down (is not concentrated at the top).

interaction:

low use of nonverbal elements. message is carried more by words than by nonverbal means.

verbal message is explicit. context is less important than words.

verbal message is direct; one spells things out exactly.

communication is seen as a way of exchanging information, ideas, and opinions.  

disagreement is depersonalized. one withdraws from conflict with another and gets on with the task. focus is on rational solutions, not personal ones. one can be explicit about another's bothersome behavior.

territoriality:

space is compartmentalized and privately owned; privacy is important, so people are farther apart.

temporality:

things are scheduled to be done at particular times, one thing at a time. what is important is that activity is done efficiently.

change is fast. one can make change and see immediate results.

time is a commodity to be spent or saved. one’s time is one’s own.

learning:

reality is fragmented and compartmentalized. one source of information is used to develop knowledge. thinking is inductive, proceeds from specific to general. focus is on detail.

learning occurs by following explicit directions and explanations of others.

an individual orientation is preferred for learning and problem solving.

speed is valued. how efficiently something is learned is important.

hope that                                         : )

answer; the above statement is (true);