What type of data includes only whole numbers that cannot take decimal values?

Discrete data consists of distinct or separate values, which are often represented by whole numbers. This type of data cannot take on fractions or decimals, making it suitable for counting specific items or occurrences, such as the number of students in a classroom or the number of cars in a parking lot. Each value in discrete data is separate; for example, you can have 1, 2, or 3 students, but not 2.5 students. This characteristic clearly differentiates discrete data from continuous data, which can take any value within a given range, including fractions and decimals. As for nominal and ordinal data, they pertain to categories and rankings respectively, rather than numerical quantities. Hence, discrete data is the correct classification for whole numbers that do not include decimal values.