Sometimes Research Requires Data Whose Availability Is Naturally Rare or Unpredictable

Sometimes research requires data whose availability is naturally rare or unpredictable. What tactic is most likely to give you such data?

A) Be patient and plan for the moment when they are available
B) Intervene to stimulate their availability artificially
C) Use data which is similar from other researchers
D) Collect very large amounts of data (over-sampling) and sift for the data relevant for your study