• Wanderlehrer in History of Agricultural Extension:
• The term Wanderlehrer (German for “wandering / itinerant teachers”) originated in Germany and Switzerland in the mid-19th century (circa 1850s).
• They were agricultural specialists who traveled from village to village to deliver lectures, conduct field demonstrations, inspect crops, and teach practical agricultural science to peasant farmers.
• The Wanderlehrer system is universally recognized in agricultural history as the earliest structured European institutional precursor to modern frontline agricultural extension education.

Correct option: (3) Itinerant agricultural teachers