Final answer:
In z/OS, the valid record format from the provided options is Fixed. Partitioned refers to dataset organization and Standard and Shifting are not recognized as z/OS record formats.
Therefore, the correct answer is: option D). Fixed
Step-by-step explanation:
Record Format (RECFM) z/OS DFSMS Using Data Sets. SC23-6855-00. RECFM specifies the characteristics of the records in the data set as fixed-length (F), variable-length (V), ASCII variable-length (D), or undefined-length (U).
When describing a data set in z/OS, the valid record formats include Fixed, Variable, Undefined and spanned.
However, among the options provided, Fixed is the valid z/OS record format.
Partitioned is a type of dataset organization and not a record format, while Standard and Shifting are not recognized as record formats in z/OS.
Mainframes (like the z/OS) support are two main file formats, Variable (V) and Fixed (F) format. They're often referred to as FB or VB (the B standing for Blocked, which is the most common way of organizing them on physical storage media).