Given G is soninlaw 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
