faceless night after elder impersonation

Hi.
if i block with a vampyre A, and the acting vampire uses Elder Impersonation at superior and i try to block with vampyre B and the acting uses superior faceless night which vampyre is locked?, both or only B?.
thanks.

Elder Impersonation
[obf] +1 stealth.
[OBF] Only usable when a minion attempts to block. The attempt fails (do not tap that blocking minion). That minion cannot attempt to block this action again.

Faceless Night
[obf] +1 stealth.
[OBF] +1 stealth, and any minion who attempts to block this action and fails becomes tapped when the action is resolved (before resolving the action).

Only B is locked

Both, all minions that attempt and fail to block are locked after the action resolves, including the target of elder impersonation, since it still counts as an attempt.

Only B because A stop to block before Faceless Night is played,so Faceless Night dont have efect on vampire A