whiCh stAtEmEnt CAn BEst ExprEss thE mAin iDEA oF this nEws itEm
A．nuClEAr tEChnology is AvAilABlE on thE BlACk mArkEt.
B．EuropEAn CountriEs hAvE Cut Down on DEFEnsE BuDgEts.
C．nAto is BEing urgED By thE u.s. to sEt up A nEw DEFEnsE systEm.
D．nAto AlliEs ArE ExpECtED to holD A summit.