An environmental survey contained a question asking what respondents thought was the major cause of air pollution in this country,
a) "automobiles,"
b) "factories,"
c) "incinerators."

A; automobiles

Step-by-step explanation:

According to the United States Environmental Protection Agency, automobiles constitutes the major cause of air pollution in the country. Automobiles accounts for more than half of the total air pollution in the United States.

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)