View the exhibit.

In the example network shown in the exhibit, switch A loses power and becomes unavailable.
Which switch ports have the designated role in instance 1 when the MSTP network converges
again?

A.
Ports A2 and B10 on switch C

B.
Ports B7 on switch D and B10 on switch C

C.
Ports A20 and B21 on switch B

D.
Ports B7 and B12 on switch D