____ frightened us ______ a tiger turned up suddenly in front of us.[ ]

A. What; was that

B. What; was

C. It; that was

D. It was; that

在向发包人索赔时，以下不得作为建设工程索赔原因的是（）。

A.因合同缺陷引起的索赔

B.因不可抗力或者意外事件导致的索赔

C.因工程变更引起的索赔

D.因承包人失误产生的索赔