Which of the following defines a normal good?

The definition of a normal good specifically refers to a good for which demand increases as consumer income rises. This positive relationship between income and demand is a fundamental characteristic of normal goods. As individuals' incomes increase, they tend to purchase more of these goods, reflecting their ability to afford higher quantities or higher quality of the products.

In contrast to the other options, a normal good is not identified as a good whose demand decreases with rising income, nor is it limited to those considered luxuries regardless of price. Additionally, a normal good is distinctly different from goods that have no direct relationship with consumer income; in this case, demand is indeed linked to income changes. Therefore, the choice that accurately encapsulates the essence of a normal good is the one stating that it has a positive income effect where demand increases as income rises.