Radio stations with radio data system (RDS) technology broadcast special program information that only radios 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 radios in Verdland was about the same in 1996 as in 1994, the number of Verdlanders receiving the special program information probably did not increase significantly.
Which of the following is an assumption on which the argument depends?

【选项】In 1996 most Verdlanders who lived within the listening area of an RDS station already had a radio equipped to receive RDS.