Which of the following types of attacks slows down or stops a server by overloading it with requests?

A DoS attack specifically works by overwhelming a server with a high volume of requests, consuming its CPU, memory, or bandwidth until it can no longer respond to legitimate traffic. This resource exhaustion through request flooding is the defining technical mechanism of a DoS attack and directly matches the scenario described. It does not require exploiting a code vulnerability or impersonating a user - simply saturating server capacity is sufficient.

An impersonation attack involves an attacker masquerading as a legitimate user or system to gain unauthorized access, which does not involve overloading a server with requests.

Network attack is an overly broad category encompassing many different attack types and does not specifically describe the technique of exhausting server resources through request flooding.

A vulnerability attack exploits a specific coding flaw or misconfiguration in software or hardware to gain access or execute code, rather than simply overwhelming server capacity with traffic volume.