The correct answer is "option 4".CONCEPT:The Acknowledgment number(ACK) is the sequence number of the next Byte the receiver is expecting.The sequence number is the Byte number of the first byte of the data in the TCP segment sent.If Synchronize packets consume one sequence number, then actual data will begin at ISN+1.?ISN, which stands for Initial Sequence Number refers to the unique 32-bit sequence number assigned to each new connection on a TCP-based communication.EXPLANATION:Option1: FALSEIf the initial sequence starts from 1 then, ACK number = 1000 means 999 bytes have been successfully received.Option 2: FALSEIf the initial sequence starts from 0 then ACK number = 1000 means 1000 bytes have been successfully received.Option 3: FALSENo chance of receiving 1001 bytes.Since the Initial sequence is not given, so we can't calculate no. of bytes received.Hence, the correct answer is "option 4".