Suppose there are two options to replace a broken yet critical machine. One is to buy a new CNC machine that has a fixed cost of $$400,000$ and a variable cost of $$4.$ The second option is to buy a used $5-$axis milling machine in pretty good shape that costs only $$40,000$ but the variable costs are $$10.$ What is the indifference point between the two options?

Question $10$Select one:

a$.$

$31,428\mathrm{.}57$ units

b$.$

None of these answers is even close

c$.$

$73,333\mathrm{.}33$ units

d$.$

$25,714\mathrm{.}29$ units

e$.$

$60,000$ units