challenge: What is a characteristic symptom of Black Leaf Streak Disease (BLSD) in plants?
  
  A. Appearance of small, dark brown streaks on the lower surface of leaves
  B. Premature ripening of the fruit without visible leaf damage
  C. Appearance of small yellow streaks on the upper side of leaves
  D. Formation of large, gray lesions on the upper side of leaves
  Answer: 