According to the context of the sentence, the word that best fits is "high" as it is speaking of something dangerous.Also, "high" is the best alternative to modify the noun "risk" taking into account the meaning as a whole.
in this case, if somenthing is dangerous, it cannot be "Low" or "medium" risk so options C and D are not suitable.
As regards the adjective "negative" it does not "collocate" with the noun "risk".
That was how I learned that Brandon's story takes place the year 9/11 happened and Reshmina's story takes place on 9/11 only 20 years later.Explanation:
