Speaker A: Well, I have to get back to the office now. It’s been really nice talking to you.

Speaker B: ()See you.

A. Glad to meet you.

B. Nice talking to you too.

C. I’ll be right back.

D. You shouldn’t leave.

根据《建设工程施工合同（示范成本）》（GF-99-0201），承包人未在索赔事件发生后28天内发生索赔意向通知，将失去请求补偿的索赔权利，说明施工索赔具有（）。

A.真实性

B.时效性

C.关联性

D.有效性