Question:  NAME_1 describes NAME_2, and NAME_3 as arguing that the withdrawal of life-sustaining treatment is morally acceptable while physician-assisted suicide is not. In their view, this is because
A: the main intention of physicians who withdraw treatment is to kill the patient, not relieve suffering.
B: the main intention of physicians who withdraw treatment is to relieve suffering, not kill the patient.
C: killing and letting die are morally equivalent.
D: many patients recover even after their treatment is withheld.
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.