How can you define a library in a SAS program?

Defining a library in a SAS program involves establishing a reference to a particular folder or directory that contains data sets, allowing users to efficiently access and manage these data sets within their SAS sessions. The correct method to achieve this is through the use of the LIBNAME statement. This statement enables the assignment of a specific library reference to a designated folder, thereby facilitating data organization and retrieval.

By using the LIBNAME statement, SAS associates a logical name (the library reference) with a physical location (the folder on the server or local machine), so that when you refer to the library reference in your code, SAS knows where to look for the data sets. For instance, an example LIBNAME statement would look like this: LIBNAME mydata 'C:\Documents\SAS\Data';, which assigns the library reference 'mydata' to the specified directory.

In contrast, the other methods mentioned do not establish library references effectively. Declaring a DATA step refers to creating a data set rather than defining a library. Listing a library name in a PROC step does not create a library either; it merely allows access to a data set already recognized as part of a library. Using a macro variable can store the library name but does not create an actual