Which of the following VMWare files can be edited by hand in case of problems?

The vmx file is indeed the correct choice for manual editing in VMWare configurations because it serves as the primary configuration file for a virtual machine. This file contains vital information about the virtual machine's hardware settings, such as the number of CPUs, amount of memory, and the virtual devices associated with the machine.

When troubleshooting or making modifications to the virtual machine's setup, an administrator can directly edit the vmx file using a text editor to correct configurations or change settings that may not be accessible through the graphical user interface of VMware.

The vmdk file, on the other hand, is a virtual disk file that contains the actual disk data of the virtual machine and should not be manually edited, as this could corrupt the data it contains. Similarly, the vmsn file is a snapshot file that stores the state of a virtual machine at a particular point in time and is managed by VMWare software, making manual edits unsafe. The vmsd file is associated with snapshot management and contains metadata about the snapshots; like vmsn, it is best left unchanged by users.

Thus, the vmx file is specifically intended for manual configuration adjustments, making it the appropriate choice for this question.