Which of the following are extraneous markings that can interfere with the correct interpretation of waveforms on an EKG tracing?

Glitches are typically associated with technical malfunctions in electronic devices but do not specifically refer to the types of distortions seen on an EKG tracing. While they may cause disruptions in signal transmission, they are not commonly used terminology in the context of EKG interpretation, making them less relevant to this question.

Smears can occur due to poor electrode contact or movement during the EKG recording, but they are not a recognized term for artifacts in EKG analysis. While they might affect the clarity of the tracing, they are not classified as extraneous markings that fundamentally alter waveform interpretation.

Lines might be present on an EKG tracing as a result of baseline wander or noise but are also not specifically categorized as artifacts. They may appear due to environmental interference or patient movement, yet they do not encompass the broader range of distortions that artifacts cover, thus making this option less precise.