Manpreet took part in an interschool race competition. He cycled 2.7 km, ran for 2⁄3 hour and walked the remaining 500 m of the race. If the total distance of the race was 12 km, then find his running speed.
A13.2 km/hr
B12 km/hr
C7.5 km/hr
D8.8 km/hr