Question

What kind of experience did the Romantics MOSTLY write about?

Answer 1

What kind of experience did the Romantics MOSTLY write about? d. Individual experiences

Answer 2

The Romantics mostly wrote about D. individual experiences. 
They were usually very sad with their lives, and would often liken the feelings of their protagonists to the weather conditions - if the hero of a poem was sad, the weather was cloudy and it was raining.