oxygen nitrogen carbon dioxide carbon monoxide
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Fertilizer from an agricultural area runs off into a river. The river carries the nutrients from this fertilizer and deposits them into an ocean bay. After the nutrients enter the bay, scientists monitoring the water would most likely see a decrease in which of these dissolved gases?
Possibilities:
- oxygen
- nitrogen
- carbon dioxide
- carbon monoxide

oxygen