Hello Lagos and Abuja NIV

How are you guys doing? I want you to guard me more on what to do. I applied for my MSc in mid 2017 for January 2018 admission, I did my F1 Visa interview at Lagos Consulate and I was denied under section 214(b) and the consular told me to reapply again. I had to deferred my admission till August 2018 and I have received my admission letter and I-20.
Now I want to complete my new DS 160, can I answer yes that I have been refused a U.S. Visa on the question page where it says "Have you ever been refused a U.S. Visa, or been refused admission to the United States, or withdrawn your application for admission at the port of entry?" Explain?? Please give me some ideals on what I can write in the explanatory box.

Sincerely,
Chuks.