From (1) G is younger than D and F.

From (5) J is younger than I and G.

From (2) E is younger than J and C.

From above 3 deductions, E is younger than D, F, I, G, J and C.

Also, from (3) C is younger than A and I.

From (4) H is younger than F and B.

From (6) G is younger than H.

From above 3 deductions,

G  is younger than F, B and H. Also, C is younger than A and I. But as seen earlier, E is younger than G and C. Hence, E is the youngest.