Which of the following pairs of goods are considered complementary goods?

Complementary goods are products that are often used together, meaning that when you buy one, you are likely to buy the other as well. For example, consider peanut butter and jelly; if you buy peanut butter, you will probably want jelly to make a sandwich. This relationship is different from inferior goods, which are items that people buy less of as their income increases, like instant noodles. In the case of complementary goods, if the price of one good goes down, people are more likely to buy more of both goods. So, if peanut butter goes on sale, you might buy more peanut butter and also more jelly to enjoy with it.