The statement that provides the most accurate investigation of why Ethiopia and Egypt have run into conflict over resource management is:
Ethiopia’s building of a dam on the Nile could impact Egypt’s use of the Nile because they lie downriver.
This statement specifically addresses the core issue of the conflict, which revolves around the management of the Nile River, a critical water resource for both nations. Ethiopia's construction of dams, such as the Grand Ethiopian Renaissance Dam (GERD), affects the flow of water downstream, which is vital for Egypt, making this the most relevant point of contention in their relationship.