Data aggregation is a fundamental problem in Wireless Sensor Networks (WSNs). From both economic and applicable concerns, designers always would like to provide guaranteed QoS of coverage of WSNs. In this paper, the authors address two path-coverage problems in WSNs, maximum k-support path coverage (a.k.a. best case coverage) and minimum k-breach path coverage (a.k.a. worst case coverage), in which every point on the desired resultant path is covered by at least k sensors simultaneously while optimizing certain objectives. They present an approaches to find optimal solutions for both maximum k-support coverage problem and minimum k-breach coverage problem.