Correct Answer: (d) 1
Solution:From figure 1 and figure 2 we get, (1 and 4) → (common faces) So, (2↔3) are opposite faces. From figure 2 and figure 3 we get, (1 and 2) → (common faces) So, (4↔6) are opposite faces. Hence, remaining (5↔1) are the opposite faces.