If the 20 mm rivets are used in lacing bars, then the minimum width of lacing bar should be A. 40 mm B. 60 mm C. 80 mm D. 100 mm

Option A is incorrect because it is less than the minimum width required for 20 mm rivets. Option C is incorrect because it is more than the minimum width required for 20 mm rivets. Option D is incorrect because it is not a valid option.