Answer:
A. consumer expectation of an increase in their future income.
Step-by-step explanation:
Supply is the quantity of a good that can be supplied by a producer to meet demand at a given time.
A left shift in supply means that there is a reduction in amount supplied at all prices.
This is caused by an increase in cost of materials used for producing goods.
A left shift can be caused by an increase in wages paid to workers. This means cost of production has increased so price per unit will increase and less will be supplied.
A decrease in number of firms will reduce the ability of suppliers to meet demand. Supply will reduce.
Anticipation of an increase in consumer income however will not lead to shift in supply to the left. Since this does not affect cost of supply