Final answer:
The term 'stride' matches the word 'walk' as it refers to a long step in the process of walking, while the other options provided do not relate to walking.
Step-by-step explanation:
In answer to the student's question about which word matches "walk", the correct option is a) stride. A "stride" is a long step or a manner of walking, and each stride can be seen as a single step in a walk.
As we compare the choices, "b) dilute" refers to making a liquid thinner or weaker by adding water or another solvent, which is unrelated to walking. "c) lunatic" is an outdated and offensive term used to describe someone with a mental illness, again, bearing no connection to the concept of walking.
Lastly, "d) cession" pertains to the formal giving up of rights, property, or territory, especially by a state, which also has no relation to the act of walking.