2
3
4
5
Answer is Wrong!
Answer is Right!
The correct answer is A. 2.
A cotter is a metal pin or wedge used to secure two or more parts together. In the case of CST-9 sleepers, cotters are used to secure the sleeper to the rail. Two cotters are used per sleeper, one on each side of the rail.
The other options are incorrect. Option B is incorrect because there are 2 cotters used per sleeper, not 3. Option C is incorrect because there are 2 cotters used per sleeper, not 4. Option D is incorrect because there are 2 cotters used per sleeper, not 5.