Hot dogs and hot dog buns are complements. An increase in the price of flour used to make hot dogs buns will: a. increase consumer surplus in the market for hot dog buns and decrease producer surplus in the market for hot dogs.
b. increase consumer surplus in the market for hot dogs and increase producer surplus in the market for hot dog buns.
c. decrease consumer surplus in the market for hot dog buns and increase producer surplus in the market for hot dogs.
d. decrease consumer surplus in the market for hot dog buns and decrease producer surplus in the market for hot dogs.

a)decrease consumer surplus in the market for hot dog buns and decrease producer surplus in the market for hot dogs

Explanation:

Hot dogs and hot dog buns are complements. An increase in the price of flour used to make hot dogs buns will decrease consumer surplus in the market for hot dog buns and decrease producer surplus in the market for hot dogs.

In economics, complements goods are ones(two goods) that their usage is very close,when there is increase in price of one, the demand of other goods that complement it falls, and from the question Hot dogs and hot dog buns are complementary goods.

consumer surplus is the difference between the price that was actually paid for a goods/service by the consumer and the price the consumer is willing to pay.

Since, Hot dogs and hot dog buns are complementary goods As the flour's price rise here consumer surplus for hot dog buns will definitely decreases, then the producer surplus decreases for hot dogs.