The thickness of bituminous carpet varies from A. 20 to 25 mm B. 50 to 75 mm C. 75 to 100 mm D. 100 to 120 mm

Option B is incorrect because bituminous carpet is not typically applied in layers that are 50 to 75 mm thick. Option C is incorrect because bituminous carpet is not typically applied in layers that are 75 to 100 mm thick. Option D is incorrect because bituminous carpet is not typically applied in layers that are 100 to 120 mm thick.