Which attack method is characterized by overwhelming a server with requests from many different sources?

The correct choice describes a Distributed Denial of Service (DDoS) attack, which is primarily characterized by the use of multiple compromised systems to flood a target server with requests. In a DDoS attack, the traffic is not only high in volume but also comes from a wide array of sources, making it challenging for the target server to distinguish between legitimate and malicious traffic.

This distributed nature of the attack allows the attacker to leverage numerous compromised devices, often part of a botnet, which collectively increase the intensity of the attack and can effectively overwhelm the server's capacity. The result is that legitimate users are unable to access the services of the server due to its resources being consumed by the immense volume of requests.

In contrast, a Denial of Service (DoS) attack typically originates from a single source, leading to denial of service to legitimate users but lacking the scale and complexity of a distributed attack. The other options involve specific types of attacks or manipulation of traffic but do not capture the essence of overwhelming a server with requests from multiple locations, which is the hallmark of a DDoS attack.