"Realist and liberal theories argue that the key structures in the international system are material, while constructivists argue that they are social and dependent on ideas" is TRUE.
Answer: Option A
Step-by-step explanation:
The formulators of Realistic and liberal theories credited visually practical factors for the reason behind overall development while constructivists found that intellectual characteristics of an era define its growth and development.
Both are correct and valid in their platform as only ideas never work, it is needed to be implemented on market and researches before such attempts need huge effort and financial support. While launching materials on random basis without matching its need and quality according to public need is also a big loss.