The Table Below Shows the Monthly Income of a Family

The table below shows the monthly income of a family and the fuel assistance received from the government. Table 33.4
Refer to Table 33.4.If the family's monthly income rises from $300 to $400, the marginal penalty on working (in terms of reduced fuel assistance) is:

A) $80
B) $40
C) $50
D) $90
E) $100