Which approach correctly initializes the length of a character variable in a DATA step?

The initialization of the length of a character variable in a DATA step in SAS is accomplished using the LENGTH statement, which is syntactically structured as "length variable-name $character-length;".

In this case, the correct option explicitly specifies both the variable name and the desired length of the character variable with the dollar sign preceding the number to indicate that it’s a character variable. For example, "length varName $5;" indicates that the variable 'varName' is a character variable that can hold up to 5 characters.

The other options do not correctly follow the syntax required for defining the length of a character variable in SAS. Setting a variable to an empty string or using incorrect syntax will not establish its length properly and does not inform SAS about the size limitation for the character variable. This can lead to unintended consequences when processing or using the variable later in the program.