单选题 Few airlines want to impose a total ban on their passengers using electronic devices because______.

A、 they don't believe there is such a danger as radio interference
B、 the harmful effect of electromagnetic interference is yet to be proved
C、 most passengers refuse to take a plane which bans the use of radio and cassette players
D、 they have other effective safety measures to fall back on

【正确答案】 B

【答案解析】依据文章第一段第四行可推断。