Verify that parallelogram abcd with vertices a(–5, –1), b(–9, 6), c(–1, 5), and d(3, –2) is a rhombus by showing that it is a parallelogram with perpendicular diagonals.

I graphed the given points and used Pythagorean theorem to get the value of each side of the rhombus.

Each side of the rhombus served as the hypotenuse of the imaginary right triangle formed in the graph. The diagonals formed are mutually bisecting and have cut each diagonal in equal parts.

Pls. see attached graph.

The answer would be the second choice : )