2024 CO CDL Practice Test: Tank - Test 4 Based on 2024 CO CDL Handbook 21. When trying to put out an electrical fire: A Use a Q extinguisher. B Use water. C Use a B or C extinguisher. D Use an X extinguisher. Next More 21/28 Progress 0 Errors Restart Next Next Tank - Test 4 Back to Test List Tank - Test 3 Tank - Test 5 Challenge Library 12 More CO CDL Practice Tests 33 Tank - Test 5 34 Air Brakes - Test 35 All - Test 36 All - Test 2 37 All - Test 3 38 Tank and Hazmat - Test 39 Tank and Hazmat - Test 2 40 Class C - Test 41 Class C - Test 2 42 Class C - Test 3