Answer = B = 26

Total span = 54 with overlap of 2 meters

Let "x" be the length of each non-overlap section

Then, x + 2 + x = 54

x = 26

Length of each arm = 26+2 = 28

Refer diagram below:

Attachment:

1.png [ 10.52 KiB | Viewed 1951 times ]
When this 28 meters arm is raised 60 degrees, it forms a 30 - 60 - 90 degree right triangle with 28 as its hypotenuse

Sides of 30:60:90 are in ratio \(1: \sqrt{3}:2\), so the side opposite to 30degree would be 14 (which is the non-cleared section of bridge)

Total clearance = 54 - 2*14 = 26

_________________

Kindly press "+1 Kudos" to appreciate