Solution: Choice C is correct.
Out-of-pocket expenses are the expenses paid by the client.
Now, client has to pay 20% of the insured expenses above 250 Dollars and a fixed expense of first 250 Dollars.
Therefore, if the total expenses insured are x (paid by client and insurance company both)
Then expenses paid by the client will be 20% (x-250) + 250.
Also, it is given that the client has not reached out-of-pocket maximum which is 5000.
Therefore, 20% (x-250) + 250 < 5000
Or 20% (x-250) < 4750
Or .2 (x-250) < 4750
Or x-250 < 23750
Or x < 24000.