The correct answer is B. 10 kmph.
In automatic section during single line working on double line in foggy weather, the speed of the first train in the right direction is restricted to 10 kmph. This is to ensure the safety of the train and its passengers. The speed restriction is in place to allow the train driver to have enough time to react to any obstacles or hazards that may be on the track.
The other options are incorrect because they are not the speed restriction that is in place for automatic section during single line working on double line in foggy weather. Option A is 15 kmph, which is too fast. Option C is 8 kmph, which is too slow. Option D is normal, which is not a specific speed restriction.
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