Which of the following describes an expression in SAS?

An expression in SAS is defined as a sequence of operands and operators that together produce a value or result. This may involve variables, constants, and various arithmetic, logical, or comparison operators. Essentially, an expression is a combination of elements that calculates a value or performs a specific data manipulation task within a data step or a procedure.

For example, in the expression x + y, x and y are operands (variables or constants) and + is the operator. This combination yields the sum of x and y. Understanding expressions is crucial in SAS, as they are central to data manipulation, conditional logic, and calculations across datasets.

Other options do not encompass the broad concept of what an expression is. A single variable is just that—a single entity without involving operations or calculations. A data step command refers to instructions that may contain expressions but is not itself an expression. A statement for inputting data pertains specifically to how data is read into SAS, which is a procedural action rather than an expression used to compute or evaluate values.