What is a key characteristic of an IF THEN statement's syntax?

A key characteristic of an IF THEN statement's syntax is that it requires the use of a semicolon to indicate the end of the statement. In SAS, semicolons are crucial as they signal the termination of statements, allowing the software to process them correctly. This means that after each conditional expression defined by the IF keyword, a semicolon must follow to ensure the statement is properly executed.

The other options do not accurately reflect the requirements for an IF THEN statement in SAS. For instance, curly braces are not used in the syntax of SAS programming. While the inclusion of an ELSE clause can provide additional logic, it is not mandatory; the IF THEN statement can operate independently without it. Regarding multiple logical operators, they may be included within a condition, but this is not a defining characteristic of the basic syntax itself. Thus, the requirement for a semicolon is essential for proper syntax and execution in SAS.