i think the answer has to be "B"..
the heading is decreasing by approx 8.6 degrees..
cause when u depart from way point 3 your hdg is 274.3..
when you arrive at way point 4 your heading is 265.6 ...
so with constant drift throughout the flight...your hdd is decreasing by less than 10 degrees....i.e. 8.6...
please correct me if i am wrong...