Task: Question Answering
Input (English): Problem: the figure above shows the dimensions of a semicircular cross section of a one - way tunnel . the single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel . if vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane , what should be the limit t on the height of vehicles that are allowed to use the tunnel ? 
Options: ['a ) 5 ½ ft', 'b ) 7 ½ ft', 'c ) 8 ½ ft', 'd ) 9 ½ ft', 'e ) 10 ft']
Output (English): b