Scientists are working hard to develop better aerials for mobile phones, a spokesman for Phikia Phones said today・'It really users when they lose the signal in the middle of a call, so we are developing new aerials that will enable users stronger signals・ Many users reported that when they (18) , the signal was often lost9, said the spokesman・ The new aerials are designed to avoid (19) the signal by receiving the message on a wider range of radio frequencies・'We (20) that this is a major concern for phone users' said the spokesman・ The new phones have a flexible external aerial, which users will have (21) touching their ear or head・ The aerials make the phones able to pick up a wider range of signals・ The company spokesman insisted (23) this was not a potential dangeru( 24) safety regulation has been followed", he told our reporter. "If (25) one of these phones this morning, I wouldn't have missed my train coming here”，joked the spokesman
选项：

A: I had
B: I'd had
C: I'd have