Which of the following might lead to an increase in the equilibrium price of meat pies and a decrease in the equilibrium quantity of meat pies sold?

a an increase in the price of tomato sauce, a complement to meat pies b an increase in the price of tacos, a substitute for meat pies c an increase in the price of beef, an input into meat pies d an increase in consumer incomes, as long as meat pies are a normal good