The maximum number of explosive wagons that can be attached to a goods train is 4. This is because the Indian Railways have a safety regulation that limits the number of explosive wagons to 4 per train. This regulation is in place to prevent accidents and to ensure the safety of the public.
Option A: 5 is incorrect because the Indian Railways have a safety regulation that limits the number of explosive wagons to 4 per train.
Option B: 4 is correct because the Indian Railways have a safety regulation that limits the number of explosive wagons to 4 per train.
Option C: 6 is incorrect because the Indian Railways have a safety regulation that limits the number of explosive wagons to 4 per train.
Option D: 10 is incorrect because the Indian Railways have a safety regulation that limits the number of explosive wagons to 4 per train.