An operations manager is about to place an order for a specific part required for the assembly of a final product. There are two companies that offer this part: Company A and Company B$.$ Fixed ordering cost from Company A is $$40,000$ and fixed ordering cost from Company $B$ is $$50,000.$ Each part ordered from Company A costs $$50,$ whereas each part ordered from Company B costs $$40.$ What is the indifference point $($The order quantity that make two options equivalent$)?$

$40,000$ units

$1,000$ units

$100$ units

$10,000$ units

$50,000$ units