What music notation indicates holding a note slightly louder or holding a note for its original length

A) ten.

B) Marc.

C) mf.

D) dim.

A) ten.

means holding the note OR making the note louder.

B) Marc.

means playing the note/passage/chord forcefully and making it louder than the other music (usualy a main piece in a band/symphony).

C) mf.

means playing the note half softer.

D) dim.

means diminishing the note (usually at the end of the music piece).

It's "A" ...