should be mounted in vertical position
should be mounted in horizontal position
either (A) or (B)
neither (A) nor (B)
Answer is Wrong!
Answer is Right!
The correct answer is: A. should be mounted in vertical position.
Switchboard instruments should be mounted in a vertical position to ensure that they are properly aligned and that the readings are accurate. If the instruments are mounted in a horizontal position, the readings may be inaccurate due to the effects of gravity.
Option B is incorrect because switchboard instruments should not be mounted in a horizontal position. Option C is incorrect because switchboard instruments should only be mounted in a vertical position. Option D is incorrect because switchboard instruments should be mounted in a vertical position.