For a particle moving along a line, the signs of its velocity v(t) and acceleration a(t) during four consecutive intervals are shown.
Interval I: 0<t<2v>0, a<0
Interval II: 2<t<4v<0, a<0
Interval III: 4<t<6v<0, a>0
Interval IV: 6<t<8v>0, a>0
On which intervals is the particle’s speed increasing?
a) Intervals I and IV
b) Intervals III and IV
c) Intervals II and IV
d) Intervals I and III