Task: Question Answering
Input (English): Problem: a regular 10 sided area is inscribed in a circle . if a and b are adjacent vertices of the pentagon and o is the center of the circle , what is the value of ∠ oab ? 
Options: ['a ) 48 degrees', 'b ) 54 degrees', 'c ) 72 degrees', 'd ) 84 degrees', 'e ) 72 degrees']
Output (English): e