What must be done before referencing an array in SAS?

To reference an array in SAS, it is essential to first define the array using an ARRAY statement. This statement specifies the name of the array and identifies the variables or elements that are part of the array. By defining the array, you establish the context within which the array elements exist, and you enable SAS to properly recognize and manipulate the specified variables as part of the array structure.

The ARRAY statement has a specific syntax that allows you to define multiple elements at once, which can simplify your code, especially when you need to perform repetitive tasks on those elements. Once the array is defined, you can then use the array's name to access its elements and perform operations on them.

The other options do not correctly represent the necessary initial steps for array usage in SAS. For instance, while declaring specific data types is a concept applicable in some programming languages, SAS implicitly understands the data types based on the variable types already defined in the dataset. Initializing the array with values, while useful for certain scenarios, is not a prerequisite before referencing the array. Additionally, creating a permanent dataset is unrelated to the array definition and does not need to occur prior to array usage.