GMATPrep CR discuss

Radio stations with radio data system(RDS) technology broadcast special program information that only radidos with an RDS feature can receive. Between 1994 and 1996, the number of RDS radio stations in Verdland increased from 250 to 600. However, since the number of RDS-equipped radions in Verdland was about the same in 1996 as in 1994, the number of Verdlanders receiving the special program informtion probably didn't increase significantly.

Which of the following is an assumption?

A:Few if any of the RDS radio stations that began broadcsting in Verdland after 1994 broadcast to people with RDS-equipped radios living in areas not previously reached by RDS stations.

B in 1996 most Verdlanders who lived within the listening area of an RDS station already had radio equipped to receive RDS.

Answer is A.  WHY?WHY?WHY?

Thank you!

因为题干开始说到the number of RDS radio stations increased from 250 to 600，又说到number of RDS-equipped radios was about the same。所以假设的条件一定要把这两点之间（radio stations和RDS-equipped radios）架一个桥。Ｂ没有做到，所以不对。

don't understand.