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.

It's "A" ...

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).