What must be included before the DATALINES statement in a data step?

The DATA statement is essential in a data step because it establishes the creation of a new data set. The DATALINES statement is used to input raw data directly within the data step. Before this statement is executed, the DATA statement must be specified to tell SAS that a new data set is being defined.

This is important because it sets the stage for the data step, allowing SAS to understand how to handle the data that follows. The presence of the DATA statement indicates to SAS that the programmer intends to read in data, either from an external source or, in this case, directly inline via the DATALINES statement. Without the DATA statement, SAS would not know that it needs to create a new data set, leading to errors when trying to read DATALINES.

Other options, such as the RUN statement, observation statements, and INPUT statement, have specific roles within a data step, but they are not mandatory before the DATALINES statement. For instance, the RUN statement is used to execute the data step after it has been defined, and observation statements generally specify the details of each observation being inputted into the data set. INPUT statements are used to define the structure of the data being read, but they come after the DATA and DATAL