Machine \(A\) can produce \(50\) components a day while machine \(B\) only \(40.\) The monthly maintenance cost for machine \(A\) is \(\$1500\) while that for machine \(B\) is \(\$550.\) If each component generates an income of \(\$10\) what is the least number of days per month that the plant has to work to justify the usage of machine \(A\) instead of machine \(B?\)

(A) 6
(B) 7
(C) 9
(D) 10
(E) 11

Answer: D

Source: GMAT Club Tests