Why are SW-3 and SW-4 behaving this way?

Referring to the exhibit, SW-3 and SW-4 have been configured for mixed-mode VCF and added to the VCF. After cabling the new devices into the VCF, you notice that SW-3 automatically joins the VCF, whereas SW-4 does not.

Why are SW-3 and SW-4 behaving this way? (Choose two.)
A . By default, QFX5100 ports are enabled as VCPs.
B . By default, QFX5100 ports are not enabled as VCPs.
C . By default, EX4300 QSPF+ ports are not enabled as VCPs.
D . By default, EX4300 QSFP+ ports are enabled as VCPs.

Answer: BD