Nationalism and exoticism.
(Also, expression may be present in Romantic music, I'm not 100% sure about that though.)
Even though is tru that the D. option is one of the characteristics of this type of music, The one that perfectly describes it is the C. option: It was performed with no instruments. This type of music is very similar to the gregorian musica and there is an absense of instruments.
Depending on weather or not you like it or hate it say Being in ensemble is an instresting/malicious time because.....
