Identify the Letter of the Choice That Best Matches the Phrase

Identify the letter of the choice that best matches the phrase or definition.
-A software add-on used to enhance a particular browser

A) bottom
B) relative positioning
C) widget sidebars
D) aside
E) header
F) wrapper
G) document flow
H) gutter
I) placeholder text
J) fixed-width
K) broken
L) fluid