3. Given points $E$ and $F$ are on the sides $BC$ and $CD$ of square $ABCD$ respectively, $\angle EAF=45^{\circ}$, and $S_{\text {square } ABCD}$ : $S_{\triangle AEF}=5: 2$. Then $AB: EF=(\quad$.
(A) $5: 2$
(B) $25: 4$
(C) $\sqrt{5}: 2$
(D) $5: 4$