There is a novel named Of Beetles and Angels by Mawi Asgedom, and his book was an extraordinary adventure from a refugee camp TO HARVARD.
His book teaches us that even if you're at the lowest point in life, try and you can get what you want.
Some people might say it is even good to mention incomplete projects, It's even better to have something already done. I would say that it would be fine to mention it, might even help.
Primary Research: Primary research usually means a primary source. For example, Primary Research can be interviewing someone, conducting research. Other examples can be observations, case studies, surveys, experiments etc. The individual directly collects information from the experiment.
Secondary Research relies on secondary sources for example using a book to prepare for a report. Secondary data can be books, articles published, statistical data, reports, and case studies.
So basically, primary research is direct contact to collect the data and secondary is using other sources rather than directly getting the information from the source. Hope this helps.
ANSWER:
C. If students form a study group, they get better grades.