From the shift-and-add method, we can determine that we need a physical address of 0b8000h. Indexes 1 and 3 in the GDT cannot be used because they would require a negative offset. Therefore, we need index 2, which implies a selector of 0010h. To find the offset, we just subtract the desired physical address from the segment base of GDT index 2. Since 0b8000h - 0b0000h = 8000h, we can determine that the required offset is 8000h. Therefore, in protected mode, with the given GDT, we need logical address 0010:8000 to access the same physical address as 0b800:0000 would in real mode.