[单选题]
04.08: The diagram sho4obtvw+k r2tdz m492 t -yl3duws a uniformly accet*nf9bo h krlt 5is--c9m ;i9tlerating ball. The position of the ballil- mf 9ttt 9hi9s5crkb;o*n- each second is indicated.
What is the average speed of the ball between 3 and 4 seconds?
A. 3.0 cm/s
B. 3.5 cm/s
C. 4.0 cm/s
D. 7.0 cm/s
E. 12.5 cm/s