RARS when run in $64-$bit mode has $64-$bit registers. But it is limited to using $32-$bit pointers. Say register s$1$ contains a pointer and its value has been saved on the stack. When restoring the pointer back to register s$1$ which of these instructions would be safer to use $($and do you know why?$)$:

Group of answer choices

lw s$1,0($sp$)$

lwu s$1,0($sp$)$