The Fieldpark nuclear power plant, cited three years ago by a governmentally led safety commission for exceeding safe levels of radiation, has recently allowed the media access to its facilities. A spokesperson for the plant has claimed that the media has full access to the plant and is not prohibited from taking pictures on the premises. The spokesperson promises that, as a result, the citizens of Fieldpark can rest assured that, until next year's governmental inspection, the facility will not exceed the federal regulations on the amount of sieverts, or radiation, to which a person can be exposed.

Which of the following is an assumption upon which the spokesperson's conclusion depends?

A. The media will publish all of the photos it deems incriminating.
B. The number of sieverts the plant releases has not increased since the last governmental inspection.
C. Communities are located close enough to the power plant to be harmed should the plant release more radiation than the regulations allow.
D. Photos can establish with the same reliability what a government safety commission can.
E. There were verifiable cases of radiation sickness in the year before the plant was cited by the safety commission

Source: Magoosh

While the OA: D is the assumption. In its answer, Magoosh states that B is classic weakner.

How come B weakens the argument?