During the first eight months of a two-year project to build a new highway, the project fails behind schedule due to a lack of machinery. To what enterprise environment factor can this be attributed? 在一个为期两年的新高速公路建设项目的前八个月中，由于缺乏一种机械，项目落后于进度计划。这属于哪一种事业环境因素？ ◑A.Organizational structure 组织结构 ◑B.Infrastructure 基础设施 ◑C.Stakeholder risk threshold 相关方风险界值 ◑D.Sustainability 可持续性
