Please help. I am most linient towards C or D. I just cant figure out which one. :

Which sentence correctly uses an intensive pronoun and would best follow the provided sentence to help convey its meaning?

All the most powerful people were there at the big celebration. _____.

A. The queen attended the event itself.
B. The queen attended the event by herself.
C. The queen attended the event herself.
D. The queen herself attended the event.

Please help fast, and thank you so much! Have a great day!