The scan output where ports are marked as "closed" suggests the use of ahalf-open or SYN scan. In a SYN scan, the scanner sends only the initial SYN packet and does not complete the TCP handshake. If a SYN- ACK is received, the port is open; if a RST is received, it is closed. This scanning method is also referred to as astealth scanand is frequently used to avoid detection. Reference: Mike Chapple, David Seidl,CompTIA CySA+ Practice Tests(Sybex, 2023), p. 376, Question 15: "This image shows a SYN-based port scan..."