A: Root Cause Analysis: Looking at the given vulnerable code line and its context, the CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerability exists in the code because the `c` variable is being freed in the while loop at line 11, but then it is attempted to be freed again at line 14 outside the loop. This can lead to a double-free scenario, which is a memory corruption issue and a violation of CWE-401.