The following figure shows a LAN topology with transparent bridges to interconnect different LAN segments. Initially, all forwarding tables are empty. The following sequence of events occurred: at first, user A attached to LAN 1 sends frame 1 to user C in LAN 4; then user B sends frame 2 to user A in LAN 1; finally, user C sends frame 3 to user B. Please show the traversing paths of frames 1 and 3, respectively Justify your answer. User A User B LAN 1 LAN 3 B1 B3 LAN 2 1 : B2 LAN 5 LAN4-2 User C