Given G is son-in-law of D.. so with this statement we can infer that G is married and D is married and are part of two different couples.
Given C is E's nephew. So now we have following two options for the family tree.
D <--> B D <--> A
/ / / /
E A <--> G E B <--> G
/ /
C C
Option 1 Option 2
Note: <--> notation is denoting a couple relation, / is denoting a parent- child relation
With option 1 of the family tree, we cannot derive a floor arrangement that satisfies the given conditions.
But option 2 of family tree we can derive a floor arrangement that satisfies the given conditions as below
7
|
C
|
6
|
|
5
|
BG
|
4
|
|
3
|
E
|
2
|
DA
|
1
|
F
|