Answer:
OB -1. They cannot stand seeing odd things . e.g in the fridge there should be 2 cooldrinks instead of 3. They prefer things in pairs.
2- They maintain and follow a strict timetable.e.g. they make sure to wake up at the same time everyday and complete tasks in an orderly manner.
3. People who suffer from OCB cannot stand untidiness at all ,so perhaps if the child cleans every single time ,that's a sign