You are lifting a 3-ton weight with a single whip rove on a swinging boom set at an angle 20° to the horizontal. Use the formula for the size of a shackle with a safe working load and determine the minimum size shackle that should be used to secure the head block to the boom.

A
1 3/8 inch
B
1 1/2 inch
C
1 5/8 inch
D
1 3/4 inch
E