Suppose during a TCP connection between A and B, B acting as a TCP receiver, sometimes discards segments received out of sequence, but sometimes buffers them. Would the data sent by A still be delivered reliably and in-sequence at B? Explain why.

Yes

Explanation:

We known that TCP is the connection protocol. So the TCP expects for the target host to acknowledge or to check that the session has been established or not.

Also the End stations that is running reliable protocols will be working together in order to verify transmission of data so as to ensure the accuracy and the integrity of the data. Hence it is reliable and so the data can be sent A will still be delivered reliably and it is in-sequence at B.