Final answer:
The supply of fast-food hamburgers is likely to decrease and push prices higher if the price of beef rises significantly. The demand for hamburgers cannot be predicted for certain if both a substitute good and complement good increase in price, as the effects counteract each other.
Step-by-step explanation:
If the price of beef rises significantly, the market for fast-food hamburgers is affected through changes in supply. Since beef is a primary input for making hamburgers, an increase in beef prices would likely decrease the supply of hamburgers, as it would become more expensive for fast-food restaurants to produce the same number of burgers. This decreased supply would typically lead to higher prices if demand remains constant, assuming the market follows basic economic principles. Therefore, the correct answer is c) Supply decreases, pushing prices higher.
Taking a closer look at the demand for hamburgers, if the price of a substitute good (like hot dogs) increases, this could lead to an increase in the demand for hamburgers since consumers might switch from hot dogs to hamburgers. However, if the price of a complement good (like hamburger buns) also increases, this could decrease the demand for hamburgers because the overall cost of the combined goods (burgers and buns) is now higher, potentially discouraging purchases.
It's not possible to predict for certain what will happen to the demand for hamburgers without additional information about consumer preferences and elasticity. We cannot discern the extent to which each of these price changes will affect demand, as these changes pull it in opposite directions. An illustrative graph would normally be provided to demonstrate how the demand curve could shift in response to these price changes, but in this format, we are unable to visualize it.