Which of the following is considered a complementary good in economics?

A complementary good in economics is defined as a product that is used together with another product. The demand for one good typically increases when the price of its complementary good decreases.

In the case of gasoline and cars, they exemplify complementary goods because cars require gasoline to function. When the price of gasoline goes down, people may be more inclined to drive their cars more frequently, thereby increasing the demand for gasoline. Conversely, if gasoline prices rise considerably, people may limit their car usage, affecting the overall demand for both cars and gasoline.

While coffee and sugar can be viewed as complementary, the relationship isn't as strong because people may drink coffee without sugar. Similarly, computers and software, while related, can exist independently; a computer can operate without any specific software. Clothes and shoes are also related, but one can easily use one without the other, making their relationship less defined as a complement compared to the strong dependency between gasoline and cars.