First write nine ten thousands in standard form which is 90,000. Next divide 90,000 by 10 and you should get 9,000 by crossing out one zero in both numbers. To get 9,000 in unit form all you have to write is 9 thousands. And your answer is 9 thousands
The answer is B as it is the only one that matches the 2 inequalities.
I think it’s 10 not sure but hope this help