C is the answer , breathing problems and air pollution relate
"I" is in regards to yourself, you and any humans name are proper nouns that you go by. "a" is not a proper noun it is describing the quantity or the subject of the matter, Ex- [I] love it when [a] cool summer day takes place in my area.
{Bad sentence, sorry}
Answer:
An architect is a person who works by the acts of planning, designing, and having control/monitoring the construction of buildings.
Explanation:
