Sallys physical education teacher timed her run and recorded the time and distance in the table below. What is her average speed?
Time (s) : 1, 2, 3, 4, 5
Distance (m) : 2, 5, 7, 10, 12
A) 3 m/s
B) 2.5 m/s
C) 2 m/s
D) 4 m/s