b$.$ With an example distinguish between physical address, logical address and offset address. If $CS=2000h,DS=3000h,SS=4000h,ES=5000h,Bx=0020,$bp$=0030$h find physical address for i$)$ MOV AL$,[$BP$]$

ii$)$ MOV CX$,[$BX$]$

iii$)$ Add AX$,20[$BX$]$

Explain the following addressing modes of $8086.$