12. Consider a virtual memory system running on a RISCCPU. Page tables are not locked in memory and may be swapped to disk. An lw (load word) instruction reads one data word from memory; the address is the sum of the value in a register and an immediate constant stored in the instruction itself. Neither machine instructions nor page-table entries nor data words can cross a page boundary. In the worst case, how many page faults could be generated as a result of the fetch, decode, and execution of an lw instruction? (A) 2 (B) 3 (C) 4 (D) 5 (E) 6