求高人指点! 逻辑10套题，excerice 10.14

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14. Neither the Sami nor the Kephrian delegations attended the international conference. Beforehand. the delegations of Daqua and Kephria. allies whose governments had grievances against Tessia. officially announced that one or both of the two would stay away if the Tessian delegation attended the conference. In response, the Sami delegation officially announced that it would definitely attend if both the Daquan and Kephrian delegations stayed away.
If the statements given are all true and all the delegations adhered to their official announcements. it must also be true that the

(A) Daquan delegation attended the conference
(B) Daquan delegation did not attend the conference
(C) Sami government had no grievance against Tessia
(D) Tessian delegation did not attend the conference
(E) Tessian delegation made no official announcement regarding its attendance at the conference

答案是E, 我怎么想都觉得应该是A呀！求高人指点呀！