What is the maximum amount of buffering that can be used to reduce the impact on the applications without impacting application throughput?

A 1 Gbps router interface to a nearby data center is showing tens of thousands of egress drops per day.

The round trip time is 2ms and the average packet size is 1000 bytes. An analysis shows that the traffic is TCP-based business application traffic. All traffic is important, so QoS will not help. You decide to increase egress buffers, keeping in mind that the TCP retransmit timer is 2*SRTT.

What is the maximum amount of buffering that can be used to reduce the impact on the applications without impacting application throughput?
A . Increase the number of buffers until the drops decreases to an acceptable level.
B . Increase the number of buffers to hold the amount of data in the TCP retransmit timer, (two times the RTT, or 4ms) of data at 1 Gbps (500 packets).
C . Increase the number of buffers to hold the amount of data in the Bandwidth Delay Product or 2ms of data at 1 Gbps (250 packets).
D . The default number of buffers is sufficient, the network is performing as it should.

Answer: B