You can see with the question alone that the plates involved is a oceanic and continental plate. With just that you can say that the answer is A. Another clue would be the <em>subduction</em><em />. This means that the plates converged, which makes it the type of boundary that occurred is <em>convergent.
The convergent oceanic-continental boundary occurs when a collision occurs between an oceanic plate and a continental plate, as with the nazca ocean plate being subdivided below the South American continental plate. The result of this is the formation of a subduction zone, since the oceanic plate is heavier and ends up below the continental plate.
