A: Root Cause Analysis: Looking at the given vulnerable code line and its context, the CWE-476 (NULL Pointer Dereference) vulnerability exists in the code because the `memcpy` function is being called with the input parameters `dest` and `src` without first checking if they are NULL pointers. If either `dest` or `src` is NULL, the `memcpy` function will attempt to access memory at a NULL pointer, which could lead to a crash or undefined behavior.