human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "peer to peer blockchain based energy trading"
  Abstract: Energy trading is evolved by the availability ofdistributed energy resources and by energy users who producemore energy than they need and can sell their excess powerfor profit. Energy trading system takes advantage of varioussources and effectively coordinates the energy to ensure efficientand optimal utilization of the available resources and providesbetter services for energy users. It achieves that goal by managingphysical, social and business infrastructures using technologiessuch as Internet of Things (IoT), cloud computing and networksystems, which facilitates both citizens and the policy makers.Peer-to-peer (P2P) energy trading is a prevailing research topicthat involves several management and technical barriers. Thispaper provides an overview of the P2P energy trading and theutilization of blockchain to enhance the efficiency and the overallperformance including the degree of decentralization, scalabilityand the security of the systems. Moreover, three blockchainbased energy trading models have been proposed to overcomethe technical challenges and market barriers for better adoptionof this disruptive technology. The paper also discusses the openissues and future directions pertaining to P2P blockchain basedenergy trading.

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.DC(Distributed, Parallel, and Cluster Computing)