You are working with a TCP connection that transmits data in packets. The connection has the following characteristics:

The sender is trying to send $4$ packets, numbered $1$ to $4.$

The following events occur:

Packet $1$ is sent and acknowledged.

Packet $2$ is sent but is lost and not acknowledged.

Packet $3$ is sent and acknowledged.

Packet $4$ is sent and acknowledged.

Questions:

Acknowledgment Behavior: What will the sender do after sending packet $2$ if it does not receive an acknowledgment $($ACK$)$ for it within the timeout period?

Retransmission: How many total packets will the sender have sent after retransmitting the lost packet?

Data Integrity: If the sender later receives an ACK for packet $2,$ what does that indicate about the reliability of the TCP connection?