Answer:
501.
Step-by-step explanation:
In Transmission Control Protocol (TCP), sending and receiving of data is done as byte. These bytes are eventually grouped into packets referred to as segment.
The sequence number of the segment if all data is sent in only one segment is the same as the first byte of that segment.
In this scenario, a user datagram connection is sending 500 bytes to a client and the first byte is numbered 501. Thus, if all data is sent in only one segment, the sequence number of the segment is 501. The 501 represents the initial segment number (ISN).
However, assuming the same data was sent in five (5) segments. The sequence number would be;
First segment (1st) = 501.
Second segment (2nd) = 1501.
Third segment (3rd) = 2501.
Fourth segment (4th) = 3501.
Fifth segment (5th) = 4501.