CONFIG_RISCV_ISA_V is not available for thedefaultarchitecture x86.
Result is shown for architecture riscv

Vector extension support

modulename: vector.ko

and/or

kernel_mode_vector.ko

configname: CONFIG_RISCV_ISA_V

Linux Kernel Configuration
└─>Platform type
└─>Vector extension support
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Add support for the Vector extension when it is detected at boot.
When this option is disabled, neither the kernel nor userspace may
use vector procedures.

If you don't know what to do here, say Y.

source code: