Answer:
The phenomenon that influenced Victor when he was younger was the moment when he witnessed a tree being struck by lightning. This part of the story serves as a foreshadow of how Victor's creation will come to life.
Explanation:
Foreshadowing is a literary technique where the author advances information that will be seen later in the story. This information is given in a non-literal, subliminal way, to make the reader curious and anxious about how the story will unfold with the influence of this information that was advanced.
An example of this can be seen in Frankenstein, when Victor witnesses a natural phenomenon that influences how Victor will bring his creature to life. In the book, when Victor was a child, he was able to witness the moment when lightning strikes a tree. At that moment Victor witnesses the great power that a ray has. This moment is an example of foreshadowing, as Victor remembers that moment and decides to use a lightning bolt to give life to his monster.
The character of Sidney in "D*cky Markle" is a minor character. She is there to serve as a complement to her father, the major character. She is also there to help the plot of the story move forward.
Had Sidney not discover the World War II medal of Richard, her deceased uncle, her father would not have remembered that past wherein D*cky was still alive and the many events that unfolded after that.
The answer would be the last one, leave it as is. B and C change the meaning of the sentence entirely, while A sounds unnatural and is too verbose.
Hope this helps! :)