Problem: a circle graph shows how the budget of a certain company was spent : 61 percent for salaries , 10 percent for research and development , 6 percent for utilities , 5 percent for equipment , 3 percent for supplies , and the remainder for transportation . if the area of each sector of the graph is proportional to the percent of the budget it represents , how many degrees of the circle are used to represent transportation ? 
Options: ['a ) 18 °', 'b ) 36 °', 'c ) 54 °', 'd ) 72 °', 'e ) 90 °']
c