What engine design at a Touring Motor Glider (TMG) results in least drag?

Question

Question Quiz SPL - Sailplane Pilot License - Principles of Flight (Aeroplane)

QuizVDS · Accepted Answer

Engine and propeller mounted stowable on the fuselage

QuizVDS · Answer

Engine and propeller mounted fix on the fuselage

QuizVDS · Answer

Engine and propeller mounted fix at the aircraft's nose

QuizVDS · Answer

Engine and propeller mounted fix at the horizontal stabilizer

Id 650 - SPL - What engine design at a Touring Motor Glider (TMG) results in least drag?