thE Country hAs AlrEADy sEnt up thrEE unmAnnED spACECrAFt, thE most rECEnt ______ At thE EnD oF lAst mAy.
A．hAs BEEn lAunChED
B．hAving BEEn lAunChED
C．BEing lAunChED
D．to BE lAunChED