The ratio of the amount of Alex's fuel oil bill for the month of February to the amount of his fuel oil bill for the month of January was \(\dfrac32.\) If the fuel oil bill for February had been \(\$40\) more, the corresponding ratio would have been \(\dfrac53.\) How much was Alex's fuel oil bill for January?
A. 240.
B. 300
C. 360
D. 450
E. 540
Answer: A
Source: GMAT Prep