What factor is likely to cause the least impact on the application layer throughput of an 802.11n client station in a 2.4 GHz HT BSS?

What factor is likely to cause the least impact on the application layer throughput of an 802.11n client station in a 2.4 GHz HT BSS?
A . Increasing or decreasing the number of spatial streams in use by the client station and AP
B . Implementation of several other clients in the same BSS using 802.11g radios.
C . Implementation Fast BSS Transition (FT) for roaming
D . RF interference from more than 10 nearby Bluetooth transmitters

Answer: B