In a consolidated drained test on a normally consolidated clay, the volume of the soil sample during shear

Answer: Option A

The correct answer is (A) decreases.

Here's why:

A consolidated drained (CD) test means we're testing a soil that is:

* Consolidated: The soil has been compressed and excess pore water pressure has dissipated.
* Drained: Water is allowed to escape freely during the shearing process.

A normally consolidated clay is a clay that has never experienced a stress greater than its current stress.

When a normally consolidated clay is sheared under drained conditions, the soil particles tend to rearrange themselves into a denser configuration.

This rearrangement and compression of the soil structure causes the overall volume of the soil sample to decrease. Because water is allowed to drain, this volume change can occur.

Therefore, the answer is decreases.