Data types for independent variables in a decision tree model must be________.

• A. numeric
• B. categorical
• C. any of the above
• D. string

Answer: (C)

Decision trees decide where to split by looking at a feature’s value and applying a rule; this splitting logic isn’t tied to one specific data type. For numeric features, the tree partitions data with a threshold (for example, x <= t versus x > t). For categorical features, it can split by categories or by groups of categories. Strings can be treated as category labels as well, or encoded to numeric codes if needed, and the tree still makes splits based on those values. Because the same flexible splitting idea applies across numeric, categorical, and string representations, independent variables can be any of these types. That’s why the best choice is “any of the above.”