Which two statements about this configuration are true?

Answer C is wrong !
Echo request from SW2 to SW1 are successful, but the Echo reply is not coming back !!!

Answers B & D seems correct

Cisco say of the ‘add’ keyword:
“add adds the defined list of VLANs to those currently set instead of replacing the list.”
So adding vlan 200 on switch doesn’t remove vlan 10.
So the ping should work?
Answers B and C correct.

Hi-ya,
The interfaces are configured as open trunks, allowing all VLANs to pass thorough the interfaces, then specific VLANs are added in all four interface configurations, which is completely pointless because all VLANs are added with the initial open trunk. The moral of the story is in the configuration, all VLANs are allowed across the two links, the “added” statements are pointless, in typical Cisco form of trying to intentionally confuse you. The end result is that all four interfaces are open trunks allowing any defined VLAN on the switches to pass over them, the top part of the config defines both VLAN 10 and VLAN 200.

So A is wrong because no VLANs are pruned anywhere in this configuration.
So D is wrong because *Only* VLAN 200 is not an accurate statement, all VLANs are allowed across the link.
B is correct not because of the “allowed vlan add” command that is in the configuration, but because the interface is configured as an open trunk and the VLANs are defined on the device and therefore added into the trunk configuration.
C is correct because VLAN 10 is allowed across the trunk and allows for pinging capability.