At the moment I would say EXOCube is neither Object B nor Object C.
OBJECT B
1 40377U 15003B 15033.17125723 -.00000113 00000-0 00000+0 0 75
2 40377 099.1264 041.9410 0165234 335.3279 024.0099 15.04186506 231
OBJECT C
1 40378U 15003C 15033.17123218 -.00000114 00000-0 00000+0 0 74
2 40378 099.1270 041.9431 0169506 333.6821 025.6050 15.04216310 233
Grifex should be easy to determine…