$1.$ Assume that converting some C code $($f $=$ g$+$h; where f$,$ g$,$ and h are all integers$)$ to MIPS assembly code is as follows: If $s$4=1000(10),$ briefly explain by drawing a picture the PC values of the $2$nd$,3$rd$,$ and $4$th instructions and the overall execution process of these three instructions. $($Ignore pipeline$/$cache$/$virtual memory$)$

$100(10)$ lw $t$1,100(10)($$s$4)$

$???(10)$ lw $t$2,104(10)($$s$4)$

$???(10)$ add $t$1,$ $t$1,$ $t$2$

$???(10)$ sw $t$1,112(10)($$s$4)$

$2.$ Explain $($complete$)$ the overall execution process of the four commands in question $1$ using the first picture below. And, using the second picture, explain the CPU's internal operating process in the case of cc$6,$ including MUX $($including MUX indication$).$