For permissible shear stress fs, the torque transmitted by a thin tube of mean diameter D and wall thickness t, is

For permissible shear stress fs, the torque transmitted by a thin tube

1.	For permissible shear stress fs, the torque transmitted by a thin tube of mean diameter D and wall thickness t, is
A.	<img src="/_files/images/civil-engineering/theory-of-structures/91-21-121-1.png">
B.	<img src="/_files/images/civil-engineering/theory-of-structures/91-21-121-2.png">
C.
D.	<i>D<sup>2</sup>t f<sub>s</sub></i>
E.	<img src="/_files/images/civil-engineering/theory-of-structures/91-21-121-4.png">
Answer» B. <img src="/_files/images/civil-engineering/theory-of-structures/91-21-121-2.png">