When three or more AND and OR conditions are combined, it is easier to use the SQL keyword(s):

Answer: Option D

Combining three or more AND and OR conditions in SQL queries can make the syntax complex and hard to read. However, using the IN and NOT IN keywords can simplify the query structure. These keywords allow for more concise and readable code when dealing with multiple conditions.
For example, instead of writing multiple nested conditions, you can use IN or NOT IN to check if a value is within a specified set of values, which can significantly improve code readability and maintainability.