A Single Mother Is Currently Paying Childcare Cost of $10

A single mother is currently paying childcare cost of $10 an hour and she works 8 hours a day.The government then provides "free" child care,raising the property tax on the mother's home by $80 a day.The effect of this event will be to

A) cause the mother to work less hours.
B) cause the mother to work the same hours.
C) cause the mother to work more hours.
D) cannot tell without knowing which effect dominates: the income or substitution effect.