challenge: What is the primary technical focus of Étude No. 11 by Villa-Lobos?
  
  A. Arpeggios and chords, with a focus on left-hand stretches and right-hand thumb use
  B. Scales and arpeggios for the right-hand fingers
  C. Double thirds and chordal passages for the left hand
  D. Rapid alternation between hands in a perpetual motion pattern
  Answer: 