Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) A Colorado man used a heartfelt Facebook video to find his first responders after collapsing at a half-marathon in Florida. Amy Smythe, 39, of Newark, Delaware, could not stop thinking about the man who had collapsed nearby, mere feet from the finish line of the Key West Half Marathon last week. She had just set a personal record, beating her previous best by 20 minutes. "It was fate that I had finished early," she said. Bill Amirault, 44, of Colorado Springs went into cardiac arrest as he was rounding the final corner of the race. Smythe, a nurse in the cardiovascular unit at Christiana Care's Christiana Hospital, wasted no time.A Colorado man who suffered cardiac arrest at a marathon found his first responders through social mediaIn his video, he urges people to learn CPR 
 Question:That's when _, who "never really used social media," had an idea: Make a Facebook video go viral.

Bill Amirault