— Could you tell me _____?

— I’m sorry. The traffic was too heavy.

A. why were you late for the meeting

B. why you were late for the meeting

C. when you were late for the meeting

某施工企业通过投标获得了某机电安装工程的施工总承包任务，该施工企业中标后的第 10天与业主签订了固定总价机电安装施工总承包合同。随后，该施工企业将部分主体工程分包给具有相应资质条件的分包人，并签订了分包合同。施工总承包合同中约定的合同工期为380天，而依施工预算定额谊工程工期应为360天。在合同履行过程中，施工总承包单位发现施工图设计文件中提供的某些工程尺寸有误，遂提出更正。

订立工程承包合同应遵循的原则是什么？