What effect will each of the following have on the supply of mobile phone?

a. A technological advance in the methods of producing mobile phone.

b. A decline in the number of firms in the mobile phone industry.

c. An increase in the prices of material used in the production of tires.

d. The expectation that the equilibrium price of mobile phone will be lower in the future than currently.

e. The levying of a per-unit tax on each mobile phone sold.

f. The granting of a 50-cent-per-unit subsidy for each mobile phone produced.