You are right - it is C
Option A would use the sense of sight to see the green truck and Option B is the sense of touch to feel the sand.
C) The Lord of the Flies reveals the dark side of human nature.
The right answer for the question that is being asked and shown above is that: "B. If you build the baseball diamond." The dependent clause in the following sentence is the B. If you build the baseball diamond
Using imagery allows authors to engage a reader's senses.