Astudent is asked to conduct a search on climate change and the contribution of greenhouse gases. the student, however, would like to avoid results that explain how a greenhouse works. which boolean search would return the most useful results?
a. using not before a keyword: greenhouse not gases
b. using or between two key words: greenhouse or gases
c. using quotation marks around the single word "greenhouse"
d. using and between the search terms: greenhouse and gases