Given the following machine instruction, what register is used as the destination register?

$\backslash$table$[[$Iw $ to$,$ o$($$t$1)$:$,1000110100101000,0000000000000000,$$zero:,$00000],[$sw $to$,0($$t$1)$:$,10101101001010000000000000000000,$$to:$,01000],[$addi $t$0,$ $t$1,15$:$,0010000100101000,0000000000001111,$$t$1$:$,01001],[$add $$t0,$$$t1,$$$t2$ :$,00000001001010100100000000100000,$$t$2$:$,01010],[$sub $$t0,$$$t1,$$$t2$:$,00000001001010100100000000100010,$$t$3$:$,01011],[$mult $t$1,$ $t$2$:$,00010001001010100000000000011000,$$t$4$:$,01100],[$mflo $to:$,00000000000000000100000000010010,$$$5$ :$,01101],[$j JLabel:,$00001000000000000000000000000101,$$t$6$:$,01110]]$

$zero

$t$4$

$ to

$ t$5$