To answer this question, you need to understand the concept of a Partitioned Dataset (PDS) and its attributes.
A Partitioned Dataset (PDS) is a file organization structure used in mainframe systems, such as IBM's z/OS. It is similar to a directory or folder in other operating systems, where it can contain multiple members or files.
The attribute of a PDS that should be modified to allow it to have members within is the "Directory blocks" attribute.
Option A) Block size - This option is incorrect because the block size refers to the size of the physical storage blocks used to store the data within the dataset. It does not affect the ability to have members within the dataset.
Option B) Directory blocks - This option is correct because the directory blocks attribute determines the number of blocks reserved for storing the directory information, which includes the list of members within the PDS. By increasing the number of directory blocks, you can allow the PDS to have more members.
Option C) Space - This option is incorrect because the space attribute determines the amount of storage allocated for the entire PDS, including the data and directory blocks. It does not directly affect the ability to have members within the dataset.
Option D) Record Format - This option is incorrect because the record format attribute determines the format of the individual records within the dataset. It does not affect the ability to have members within the dataset.
Therefore, the correct answer is option B) Directory blocks. By modifying the directory blocks attribute, you can allow a PDS to have members within.