Screws are specified by their __________ diameters.

ANS:B - major

In screw threads, the major diameter refers to the largest diameter of the screw thread. It is the outer diameter of the threaded portion of the screw. This diameter is essential for determining the size of the hole needed for the screw to fit properly. The major diameter is measured across the peaks of the threads on the external surface of the screw. It is one of the primary dimensions used to specify the size of a screw.