Answer :
An elegiac broadside is A MOURNFUL, PLAINTIVE BALLAD
An elegy is a poem of lamentation to mourn the loss of something or someone. And broadside can mean a verbal attack. So the definition, a mournful, plaintive ballad fits best here.
The correct answer is plaintive ballad and mourning.
Elegiac broadside itself is a type of ballad which has a plaintive feel and which is mournful.
It is a poetry which tells the story of a life which is being lost. An elegiac broadside is being got from mournful feeling of a poetry.
If a story is being taught like a ballad, it is being recited for a person who has died.
The broadside is the paper which contains the announcements, the public information and the elegies.
A famous example of an elegiac broadside is the elegy.