Step 1: Understanding the question.
The question asks for the bearing of an object when the position is interchanged. The bearing is initially given as 60°E from the observer.
Step 2: Analyzing the solution.
To interchange the bearing, we need to calculate the opposite direction. The front bearing is 60° from the observer; its opposite will be 180° apart, which means the new bearing from the North will be 120° clockwise.
Step 3: Conclusion.
The correct answer is 120°.