What is the following sequence of packets demonstrating?

This packet shows telnet.com (the server) sending the initial FIN to the client, meaning it represents the server-initiated half-close, not the client's FIN.

This packet shows client.com sending only an ACK (dot notation indicates no FIN flag) to acknowledge the server's FIN - it does not itself initiate the client-side connection close.

Packet C shows client.com sending a FIN segment (F flag) to telnet.com, which is the client initiating the closure of its side of the TCP connection. In a TCP graceful close, after the client acknowledges the server's FIN in packet B, it must send its own FIN segment to complete the four-way termination handshake - this is exactly what packet C represents with sequence number 92 and the F flag set.

This packet shows telnet.com sending an ACK for sequence 93 to acknowledge the client's FIN, completing the four-way close from the server side, not initiating the client-side close.