During two equal time intervals of 30days, a planet sweeps equal small areas near points P and Q of its elliptical orbit. Its distances from the Sun are 0.5AU at P and 1.0AU at Q. If sP and sQ are the arc lengths travelled in these intervals, which relation is correct?
(a) sP=sQ
(b) sP>sQ
(c) sP<sQ
(d) sP=21sQ