They change shape due to a number of reasons.
The easiest reason to understand why they change is that they erode.
The coasts around the the world erode due to waves hitting cliffs, the wind batting against the coasts etc. Over a long period of time we can see that they change in shape.
(sorry I don't know why they move)
Answer: inferred
An inferred meaning is one that is not explicitly stated by the author, but that is hinted at throughout a passage. This is usually done through the use of various rhetorical and literary devices, such as characterization, symbols, motifs, setting and mood.
I believe there is a mistake in your choices, because I don't see the correct choice here. The correct answer should be ABAB ABCB.
This is because in the first stanza, the first line A (son) rhymes with the third line A (shun), and the second line B (catch) rhymes with the fourth line B (Bandersnatch) - which makes the first stanza ABAB.
In the second stanza, the first line A doesn't rhyme with anything (hand), the second line B (sought) rhymes with the fourth line B (thought), and the third line C doesn't rhyme with anything - which makes the second stanza ABCB.
Transition words I believe
