default or selected kernelversion does not have config value CONFIG_ND_BLK.
Result is shown for kernelversion 6.9.5

BLK: Block data window (aperture) device support

modulename: nd_blk.ko

configname: CONFIG_ND_BLK

Linux Kernel Configuration
└─>Device Drivers
└─>NVDIMM (Non-Volatile Memory Device) Support
└─>BLK: Block data window (aperture) device support
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Support NVDIMMs, or other devices, that implement a BLK-mode
access capability. BLK-mode access uses memory-mapped-i/o
apertures to access persistent media.

Say Y if your platform firmware emits an ACPI.NFIT table
(CONFIG_ACPI_NFIT), or otherwise exposes BLK-mode

source code: