4. Among the following four figures, which one has the largest area?
(A) $\triangle A B C: \angle A=60^{\circ}, \angle B=45^{\circ}, A C=\sqrt{2}$;
(B) Trapezoid: the lengths of the two diagonals are $\sqrt{2}$ and $\sqrt{3}$, and the angle between them is $75^{\circ}$;
(C) Circle: radius is 1;
(D) Square: the length of the diagonal is 2.5.