A. Harmless
B. Subtly harmful
C. Obvious
D. Benign
Answer: Subtly harmful
A. Harmless
B. Subtly harmful
C. Obvious
D. Benign
Answer: Subtly harmful
Additional Information: 'Insidious' means proceeding in a gradual, subtle way, but with harmful effects.
Subjects: Context Clues, Reading Comprehension