What Prussian Army officer is credited with training American soldiers in essential military skills while they were encamped at Valley Forge?

What Prussian Army officer is credited with training American soldiers in essential military skills while they were encamped at Valley Forge?

Peter Muhlenberg
Philip Schuyler
Count von Donop
Hans Daniel Hassenpflug
Baron von Steuben

Correct Answer: Baron von Steuben