Side-channel attacks, as explained in CEH v13 OT and SCADA Security, extract sensitive information by observing physical characteristics of a system rather than exploiting software flaws directly. These characteristics may include power consumption, electromagnetic emissions, timing variations, or thermal output.

In SCADA environments, side-channel attacks are especially dangerous because they bypass traditional network defenses. The most reliable way to confirm such an attack is by analyzing hardware-level anomalies—such as unexpected power usage spikes or irregular signal emissions during normal device operations.

Option B directly aligns with CEH v13 guidance.

Options A, C, and D focus on software, cryptography, or network behavior, which are not primary indicators of side-channel exploitation.

Therefore, Option B is correct.