A user tries to telnet into a system that was previously accessible but gets the following error:  "telnetd: 0403-031 fork function failed, there is not enough memory available."  netstat -m shows that 0 mbuf errors have occurred.  Which of the following conclusions is most appropriate to draw about this error?（）

A. The paging space is full.
B. A particular filesystem is full and cannot be allocated to memory.
C. A problem exists with telnetd. 
D. The inetd daemon went down.