Final answer:
The correct answer is a header, which is the structural element used to support the load above windows and doors in wall framing, ensuring the integrity of the structure.
Step-by-step explanation:
The horizontal framing member used to tie together interior and exterior wall framing is known as a header. Option 3 on your list is correct. The header is a structural element that is installed over window and door openings to carry the load of the structure above. It bridges the gap above the opening and transfers the load to the vertical studs on either side of the opening. Headers are crucial in maintaining the integrity of the wall structure and preventing sagging or collapse above window and door frames.