单选题：根据下列文章,请回答题。Mobile PhonesMobile phones should carry a label

根据下列文章,请回答题。Mobile PhonesMobile phones should carry a label if they proved to be a dangerous source of radiation, according to Robert Bell, a scientist. And no more mobile phone transmitter towers (发射塔) should be built until the long-term health effects of the radiation they emit(放射) is scientifically evaluated, he said. "Nobody's going to drop dead overnight but we should be asking for more scientific information," Robert Bell said at a conference on the health effects of low-level radiation. "If mobile phones are found to be dangerous, they should carry a warning label until proper shields can be devised," he said.
A report widely circulated (传播) among the public says that up to now scientists do not really know enough to guarantee there are no ill effects on humans from radiation. According to Robert Bell, there are 3.3 million mobile phones in Australia alone and they are increasing by 2,000 a day. By the year 2000 it is estimated that Australia will have 8 million mobile phones: nearly one for every two people.
As well, there are 2,000 transmitter towers around Australia, many in high density(密度) residential areas. For example, Telstra, Optus and Vodaphone build their towers where it is geographically suitable to them and disregard the need of the community. The radiation emitted from these towers may have already produced some harmful effects on the health of the residents nearby.
Robert Bell suggests that until more research is completed the government should ban construction of phone towers from within a 500 meter radius (半径) of school grounds, child care centers, hospitals, sports playing fields and residential areas with a high percentage of children. He says there is emerging evidence that children absorb low-level radiation at a rate more than three times that of adults. He adds that there is also evidence that if cancer sufferers are subjected to radiation the growth rate of the disease accelerates (提高).
Robert Bell calls on the major telephone companies to fund adequate research and urges (敦促) the government to set up a wide ranging inquiry into possible health effects.According to Robert Bell, if mobile phones prove to be dangerous to people's health, A．they should be banned immediatel
B．the use of them should be restricte
C．all transmitter towers should be torn dow
D．a warning label should be attache