Which layer of the NTP hierarchy is characterized by being the least accurate?

The layer of the NTP (Network Time Protocol) hierarchy that is characterized by being the least accurate is Stratum 3. In the context of NTP, stratum levels are used to indicate the distance from an authoritative time source.

Stratum 0 represents high-accuracy time sources, such as atomic clocks or GPS clocks, and is not directly accessible over the network. Stratum 1 servers are those that are directly connected to Stratum 0 devices and acquire time information from them, making them highly accurate as well. Stratum 2 servers obtain time information from Stratum 1 servers, introducing a slight degradation in accuracy due to network delays and latency.

As you move further down the hierarchy, Stratum 3 servers receive their time updates from Stratum 2 servers. This distance from the primary time source results in a decrease in accuracy. Each subsequent stratum level adds potential network latency and reduces accuracy, with Stratum 3 being less accurate than the higher strata.

Thus, Stratum 3 is the correct answer because it is at a further remove from the primary time sources, making it the least accurate layer in the NTP hierarchy.