When you subnet an IPv$6$ address you use

$32$ bits for the network $32$ bits for the subnet and $64$ bits for hosts$/$interfaces

$64$ bits for the network $32$ bits for the subnet and $32$ bits for hosts$/$interfaces

$64$ bits for the network $48$ bits for the subnet and $16$ bits for hosts$/$interfaces

$48$ bits for the network $16$ bits for the subnet and $64$ bits for hosts$/$interfaces