Answer: 1. inferior goods
2. complementary goods
3. increase in the demand
Explanation: 1. In simple words, inferior goods refers refers to those goods the price and quantity demand for which have a negative relationship. These are usually low quality goods.
2. Complementary goods refers to the goods which are used jointly. The price and demand for complementary goods have negative relationship.
3. When the demand for a good increases due to other factors than price than such increase is called increase in demand and not quantity demanded.