Which two types of spanning tree protocols can cause suboptimal traffic flows because they assume only one spanning-tree instance for the entire bridged network?

A. Multiple Spanning Tree Protocol (MSTP)
B. Per-VLAN Spanning Tree Plus (PVST+)
C. Spanning Tree Protocol (STP) (IEEE 802.1D)
D. Rapid Spanning Tree Protocol (RSTP) (IEEE 802.1w)