challenge: What was the event that led to the incursion that finally ended Roberto Cofresí's pirate operation?
  
  A. A negotiation with the Spanish government in Puerto Rico
  B. A request for international sloops from the Danish governor
  C. A report of Anne's hijacking by Low to Sloat
  D. A sighting of Cofresí's ship by a Colombian frigate
  Answer: 