19. The "2016 Nobel Prize in Physiology or Medicine" was awarded to Dr. Yoshinori Ohsumi "for his discoveries of mechanisms for autophagy". Which of the following statement about autophagy is incorrect? (A) A mitochondrion was observed being engulfed by a cup-shaped double-membrane. This mitochondrion might be going through the process of autophagy. (B) In autophagy, the engulfed organelles will be sent to the 26S proteosome for degradation. (C) Autophagy mediates the digestion and recycling of non-essential parts of the cell during starvation. (D) Autophagy is capable of clearing invading microorganisms and toxic protein aggregates.