Sosenuto - yes or no? (Debussy)

[yqxpiano]

So, I am playing a piece by Debussy. Called pour le piano, prelude.
Starting measure six, should I use sostenuto to hold down the low a note in the left hand?
If not, any advice to make it hold longer with just the damper pedal?

[bryfarr]

yes, definitely - my score even has it marked

[lelle]

My teacher who I played this for told me that the piece was written specifically to make use of the sostenuto pedal, which was a new invention at the time.