This is what the Galvin text has to say. Usually, there are two types of signal handlers: Kernel Level and user level. Now the kernel level is the default one. But if we look at the wordings of the question in details :
A user level process in Unix traps the signal sent on a Ctrl-C input, and has a signal handling routine that saves appropriate files before terminating the process.
It clearly means that the signal handling routine is a part of the user-level process and hence it shall run in user mode.
Ans: (A) USER MODE