What is the name of the full length stud that a jack stud is fastened to?

The full-length stud that a jack stud is fastened to is called the king stud. In framing, the king stud runs the full height of the wall and provides support for the header above openings, such as doors and windows. The jack stud, which is shorter than the king stud, is attached alongside it and helps to support the weight from the header. This dual-stud configuration is essential for maintaining the structural integrity of the wall around openings.

The other choices relate to different components in carpentry but do not serve the same function as the king stud in relation to the jack stud. For example, a header is a structural element spanning the space above a door or window but does not provide vertical support itself. Base stud and corner stud refer to different specific roles in framing that do not involve the configuration of jack and king studs. Understanding this relationship between the jack and king stud is crucial for proper wall framing techniques.