Each month, a certain manufacturing company's total expenses are equal to a fixed monthly expense plus a variable expense that is directly proportional to the number of units produced by the company during that month. If the company's total expenses for a month in which it produces $20,000$ units are $$570,000,$ and the total expenses for a month in which it produces $25,000$ units are $$705,000,$ what is the company's fixed monthl expense?

A$.$ $$27,000$

B$.$ $$30,000$

C$.$ $$67,500$

D$.$ $$109,800$

E$.$ $$135,000$