Final answer:
In the context of a slump or landslide, the toe of the earth material generally spreads outward due to the loss of support and the influence of gravity.
Step-by-step explanation:
When a slump occurs, such as in the context of a landslide or earth movement, the material at the bottom known as the toe will typically spread outward. This spreading happens because the material loses its supporting structure and gravity causes it to flatten out and move down the slope. Consequently, the correct answer for the question would be (a) Spread outward.