Answer: □ABCD is a parallelogram.
Distance formula: \(d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\).
\(AB=\sqrt{1+25}=\sqrt{26}\), \(BC=\sqrt{36+25}=\sqrt{61}\), \(CD=\sqrt{1+25}=\sqrt{26}\), \(DA=\sqrt{36+25}=\sqrt{61}\).
Opposite sides are equal, so it is a parallelogram. Adjacent sides are unequal, so it is not a rhombus.
Diagonals: \(AC=\sqrt{49+0}=7\), \(BD=\sqrt{25+100}=\sqrt{125}\). They are unequal, so it is not a rectangle. Hence ABCD is just a parallelogram.