Which of the following is the correct procedure of auscultation of lungs? A: Auscultate from the top to the bottom and compare the anterior side with the posterior side. B: Auscultate from the top to the bottom and compare the left side with the right side but avoid heart area. C: Auscultate from the bottom to the top and compare the anterior side with the posterior side. D: Auscultate from left to right and compare the anterior side with the posterior side. E: Random auscultation spots without comparison