A car starts from rest, accelerates uniformly at 2 m s⁻² for 5 s, then continues at the speed reached for 10 s, and finally decelerates uniformly to rest in 4 s. The average velocity for the entire journey is closest to
(a) 10m s−1
(b) 5m s−1
(c) 7.6m s−1
(d) 8.3m s−1