A 45-Year-Old Woman Comes to the Office Due to Several

A 45-year-old woman comes to the office due to several weeks of nonproductive cough and dyspnea. She underwent lung transplantation 7 months ago because she has a history of primary pulmonary hypertension. She takes her medications regularly. Pulmonary function testing demonstrates a forced expiratory volume in 1 second (FEV₁) , 67% of her best posttransplant FEV₁.  Her forced vital capacity remains largely unchanged.  A lung biopsy shows areas of total fibrotic obstruction in the terminal bronchioles.  This patient's condition is most likely caused by which of the following?

A) Acute transplant rejection
B) Chronic obstructive pulmonary disease
C) Chronic transplant rejection
D) Ischemia-reperfusion injury
E) Opportunistic infection
F) Recurrence of pulmonary hypertension