Refer to the exhibit.

Switch S2 contains the default configuration. Switches S1 and S3 both have had the command spanning-tree mode rapid-pvst issued on them.
What will be the result?

A.
IEEE 802.1D and IEEE 802.1w are incompatible. All three switches must use the same
standard or no traffic will pass between any of the switches.

B.
Switches S1, S2, and S3 will be able to pass traffic between themselves.

C.
Switches S1, S2, and S3 will be able to pass traffic between themselves. However, if
there is a topology change, Switch S2 will not receive notification of the change.

D.
Switches S1 and S3 will be able to exchange traffic but neither will be able to exchange
traffic with Switch S2

Explanation:
Cisco Catalyst switches support three types of STPs, which are PVST+, rapid-PVST+ and
MST. PVST+ is based on IEEE802.1D standard and includes Cisco proprietary extensions
such as BackboneFast, UplinkFast, and PortFast. Rapid-PVST+ is based on IEEE 802.1w
standard and has a faster convergence than 802.1D. RSTP (IEEE 802.1w) natively includes
most of the Cisco proprietary enhancements to the 802.1D Spanning Tree, such as
BackboneFast and UplinkFast. Rapid-PVST+ uses the same BPDU format as the 802.1D
and it is backward compatible. It is difficult to convert all the switches in the enterprise
network at the same time to rapid-PVST+. Because of the backward compatibility, you can
convert phase by phase.