Eight persons — A, B, C, D, E, F, G, and H are sitting around a circular table facing toward the center, but not necessarily in the same order. Also, each of them is holding number cards from 2 to 9 (one card per person). The numbers on their cards are distinct. Consecutive numbered card holders are not sitting adjacent to each other. B is sitting second to the left of the person holding the card numbered 7. The person holding the card numbered 3 is sitting second to the right of E, who holds an even-numbered card greater than 4. C holds a card whose number is a prime number, but C is not sitting adjacent to either B or the person holding the card numbered 9. The person holding the card numbered 9 is sitting immediately to the right of A, who holds a card number divisible by both 2 and 4. The difference between the numbers on the cards hold by D and the person sitting opposite D is 3. The person holding the card numbered 2 sits third to the left of the person holding the card numbered 6. The sum of the numbers on the cards hold by G and the person sitting to G's immediate right is 11. The person holding the card numbered 4 is sitting opposite the person holding the card numbered 8. What is the card number held by the person seated opposite to B?

### Concept & Logic This question relies on accurately mapping the specific pairs of individuals sitting diametrically opposite each other in an 8-person circular table. ### Step-by-Step Solution 1. **Locate $B$ in the arrangement:** * The puzzle states $B$ is second to the left of the person holding card 7. * Through full derivation, we established that $G$ holds 7 and sits at Position 8. * Left is clockwise. Second to the left of Position 8 is Position 6. Therefore, $B$ is seated at Position 6. 2. **Determine $B$'s card:** * The clues dictate that the person holding 2 is third to the left of the person holding 6. This perfectly aligns with Position 3 (holding 2) and Position 6 (holding 6). So, $B$ holds the card numbered 6. 3. **Identify the opposite position:** * In an evenly spaced 8-person circle, a person at position $P$ is opposite the person at position $P+4$ (or $P-4$). * Opposite Position 6 is Position 2. 4. **Identify the occupant of Position 2:** * Based on our primary derivation, $A(4)$ is at Pos 1, and the person with 9 is immediately to $A$'s right (anti-clockwise) at Pos 2. * Furthermore, the difference between $D$ and the person opposite $D$ is 3. The cards at Pos 2 (9) and Pos 6 (6) have a difference of exactly 3. Since $B$ is at Pos 6, $D$ must be at Pos 2, holding the card numbered 9. * Thus, the person opposite $B$ holds the card **9**. ### Exam Strategy & Shortcut If you have successfully mapped out the table, this is a simple lookup question. Always draw a clear, large diagram of the circle on your scratch paper to ensure opposite pairs are visually perfectly aligned, eliminating calculation errors. ### Common Pitfall A common mistake is misidentifying opposite pairs by counting incorrectly around the circle. Always remember the $P+4$ rule for an 8-person table. ### Final Answer Therefore, the correct answer is **9**.