What is the speed for both rural and urban school zones and during what times (unless otherwise posted)?

a) 30 km/h from 8 a.m. to 5 p.m.
b) 40 km/h from 8 a.m. to 5 p.m.
c) 50 km/h from 7 a.m. to 4 p.m.
d) 30 km/h from 7 a.m. to 4 p.m.