问题：

[单选] You have done a partial migration from 802.1D STP to 802.1w STP. Which of the following is true？（）

A . 802.1D and 802.1w interoperate only when the 802.1D STP domain supports rapid convergence.
B . Ports leading to 802.1D devices will run in compatibility mode， while the rest of the ports will run in 802.1w mode.
C . This is an invalid configuration and a partial migration cannot be done.
D . The bridge timers will be set to match the 802.1D devices.
E . A secondary root bridge will always be populated within the 802.1D domain.
F . If the root bridge is selected within the 802.1D domain， the whole STP domain will run in 802.1D compatibility mode.
G . In partially migrated 802.1w networks， it is recommended to keep the STP diameter below 4.