Which event directly led to beginning of world war z

Although the origin of the zombie pandemic is unknown, the story begins in China after an unknown creature bites a young boy (who becomes the official Patient Zero). The Chinese government attempts to contain the infection and concocts a crisis involving Taiwan to mask their activities.

FYI: I am talking about the movie

answer; i do believe that the answer is (c) electrolyte imbalance or (d) cessation of menstrual cycle; plz check first good luck

good question. i'll be looking into that. (this is a joke sir)