Which of the following commands would create a permanent dataset named "mydata" in the “data” library?

The command that creates a permanent dataset named "mydata" in the "data" library is formulated as "DATA data.mydata;". This syntax indicates that you are specifying the library (in this case, "data") where the dataset will be stored, followed by the name of the dataset ("mydata"). In SAS, permanent datasets are created by referencing a library that has been defined as permanent.

To create a permanent dataset, the library must exist and be appropriately defined with a LIBNAME statement pointing to a directory on disk. When you use "DATA data.mydata;", it tells SAS to place the dataset in the "data" library, ensuring that it retains its existence even after the SAS session ends.

Other options do not achieve the same results due to their syntax or references. For example, creating a dataset in the WORK library (as in the first choice) leads to the dataset being temporary, and options that include incorrect syntax or references such as LIB or IN modifiers do not align with how SAS interprets dataset creation. Hence, the identifying features of the command in the correct choice facilitate the creation of a dataset in a specified permanent library successfully.