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.