Seven persons A, B, C, D, E, F and G sit in a row facing north. They have different elements named copper, nickel, gold, mercury, aluminum, silver and iron. The information is not used in the same order as given. The one who have gold sits third to the left of D, none of them sits at any of the extreme ends. E sits immediate right of the one who have gold. B and E sit adjacent to each other. The one who have iron sits second to the left of B. Two persons sit between G and F. The one who has mercury sits fourth to the right of G. The one who have copper sits immediate right of the one who has silver. The one who have nickel sits to the left of F and to the right of A.

Who among the following have silver?

To find the person who has silver, let us analyze the clues step-by-step to determine the seating arrangement and the element associated with each person. There are 7 positions in a row, numbered 1 to 7 from left to right (facing north).

Step 1: Determine the positions of the Gold-holder, D, and E
- The one who has gold sits third to the left of D.
- Neither the gold-holder nor D sits at the extreme ends (positions 1 and 7).
This means the position of the Gold-holder must be either 2 or 3, making the position of D either 5 or 6, respectively.
- E sits to the immediate right of the one who has gold. Thus, if Gold is at 2, E is at 3; if Gold is at 3, E is at 4.

Step 2: Determine the positions of B and the Iron-holder
- B and E sit adjacent to each other.
- The one who has iron sits second to the left of B.
Let's test the two cases:
- Case 1: Gold is at 2, E is at 3, and D is at 5. B must be at 2 or 4. If B is at 2, second to the left would be position 0 (invalid). If B is at 4, second to the left is position 2, which already has Gold (contradiction, as elements are different). Thus, Case 1 is eliminated.
- Case 2: Gold is at 3, E is at 4, and D is at 6. B must be adjacent to E (positions 3 or 5). If B is at 5, the second to the left is position 3 (which has Gold, contradiction). Thus, B must be at position 3, meaning B has gold, and the person at position 1 (second to the left of B) has iron.

Step 3: Place G, F, and Mercury
At this stage, the arrangement is:
1: [Iron], 2: [ ], 3: B [Gold], 4: E [ ], 5: [ ], 6: D [ ], 7: [ ]
- Two persons sit between G and F.
- The one who has mercury sits fourth to the right of G.
If G is at position 2, then Mercury is at position 6 (which is D), and F must be at position 5 (leaving 3 and 4 between G at 2 and F at 5). This satisfies all conditions.
So, G is at 2, F is at 5, and D (at 6) has mercury.

Step 4: Place Silver, Copper, Nickel, and A
Our arrangement is now:
1: [Iron], 2: G [ ], 3: B [Gold], 4: E [ ], 5: F [ ], 6: D [Mercury], 7: [ ]
- The one who has copper sits to the immediate right of the one who has silver. The only adjacent empty slots for elements are at positions 4 and 5. Therefore, E (at 4) must have silver and F (at 5) must have copper.
- The one who has nickel sits to the left of F and to the right of A. F is at 5, so Nickel must be to the left of 5. The only remaining element slot to the left of 5 is position 2 (G). Thus, G has nickel. Since Nickel is to the right of A, A must be to the left of G (position 2), placing A at position 1.
- The remaining person C is placed at position 7, and the remaining element aluminum is assigned to C.

Final Seating and Element Arrangement:
1. A (Iron)
2. G (Nickel)
3. B (Gold)
4. E (Silver)
5. F (Copper)
6. D (Mercury)
7. C (Aluminum)

Therefore, E is the person who has silver.