If is the angle of deflection of a simple curve of radius R, the distance between the mid-point of the curve and long chord, is

If is the angle of deflection of a simple curve of radius R, the dis

1.	If is the angle of deflection of a simple curve of radius R, the distance between the mid-point of the curve and long chord, is
A.	<img src="/_files/images/civil-engineering/surveying/63-3.188-1.png">
B.	<img src="/_files/images/civil-engineering/surveying/63-3.188-2.png">
C.	<img src="/_files/images/civil-engineering/surveying/63-3.188-3.png">
D.	<img src="/_files/images/civil-engineering/surveying/63-3.188-4.png">
E.	.
Answer» E. .