Which one of the following screw thread forms has an included angle of 29 Degree between the flanks of thread ?

Screw thread micrometer

Screw thread micrometer is used to measure the effective diameter of the screw threads. This dimension is important, because the area of the thread flanks in the vicinity of the pitch line is where the greatest transmission of force occurs between mating threads.

Helical grooves

A screw thread is formed on a cylindrical surface by cutting Helical grooves on its surface.

Round

The root of ISO metric thread is Round

Saw-tooth thread

In Saw tooth threaded assembly sliding force acts in one direction only.