Ethernet operates at all speeds except which of the following?

Ethernet standards have defined a range of speeds over the years, beginning from basic configurations to high-speed networking. The common Ethernet speeds include 10 Mbps (10Base-T), 100 Mbps (Fast Ethernet), 1 Gbps (Gigabit Ethernet), and up to 400 Gbps in newer standards.

When evaluating the speeds mentioned, 32 Kbps, 64 Kbps, and 128 Kbps can be considered special cases or are not widely used in standard Ethernet implementations. Historically, Ethernet technology developed significantly beyond low speeds like these, and therefore, these values are not recognized in mainstream Ethernet specifications.

However, 16 Kbps is notably outside the typical progression of Ethernet standards. While Ethernet does encompass a variety of connection speeds, 16 Kbps does not correlate to any established Ethernet framework or protocol and represents a speed that is lower than most definitions of Ethernet performance. This makes it the outlier among those options.

Therefore, the correct answer, representing a speed not operated by Ethernet, is 16 Kbps. The inclusion of the other speeds could tie into alternative communication protocols or legacy systems that do not fall within the domain of standard Ethernet networking.