The correct answer is: B. 725
When the platform level is 725 mm and more, second arriving train shall not be received and berthed on non platform line directly. This is because the difference in height between the platform and the train can cause passengers to trip and fall. Additionally, it can be difficult for passengers to board and disembark from the train if the platform is too high.
Option A: 700 mm is the minimum platform height required for passengers to board and disembark from a train safely. However, if the platform level is 725 mm or more, it is recommended that second arriving trains be received and berthed on platform lines instead of non platform lines. This is because the difference in height between the platform and the train can cause passengers to trip and fall.
Option B: 725 mm is the recommended platform height for receiving and berthing second arriving trains. This is because the difference in height between the platform and the train is less likely to cause passengers to trip and fall. Additionally, it is easier for passengers to board and disembark from the train if the platform is at the same level as the train.
Option C: 650 mm is the minimum platform height required for passengers to board and disembark from a train safely. However, if the platform level is 650 mm or less, it is not recommended that second arriving trains be received and berthed on non platform lines. This is because the difference in height between the platform and the train can cause passengers to trip and fall.
Option D: 760 mm is the maximum platform height allowed for receiving and berthing second arriving trains. This is because the difference in height between the platform and the train can cause passengers to have difficulty boarding and disembarking from the train. Additionally, it can be dangerous for passengers to walk on a platform that is too high.