A company can produce 100 units of a component part with total variable cost of $ 75,000 and fixed cost of $ 22,000. These component units can be purchased externally at price of $8 per unit. Fixed costs are not avoidable. By what amount will its total costs change if they purchase externally ?

a	an increase of $17,000
b	a decrease of $17,000
c	an increase of $5,000
d	a decrease of $5,000