Which of the following statements regarding unstable soil in conduit routes is correct?

The statement that unstable soil in conduit routes should be avoided to prevent conduit failure is correct. This is because unstable soil can lead to shifting and settling, which can damage or displace conduits. Such soil conditions may not provide the necessary support or stability for the conduits, leading to issues such as cracks, breaks, or misalignment. Ensuring that the installation occurs in stable, well-compacted soil is critical for the longevity and effectiveness of underground systems.

In contrast, other options suggest that unstable soil might enhance conduit performance or be preferable for installations, which misrepresents the realities of construction and soil mechanics. Supportive soil conditions are essential for maintaining the integrity and functionality of underground installations, thus reinforcing the necessity of avoiding unstable soil.