Answer:
c. (5, -2)
Explanation:
as we can clearly see, the 4th vertex has to be on the positive side of x.
therefore, all answer options with negative x are out.
(2, -5) is almost at D (-1, 5). that cannot be right for a rectangle.
that leaves only c as right answer.
FYI - how to get this without predefined answer portions ?
the x- difference of B to A is 4 (from -5 to -1). the x-difference from D to C must be the same (4). 1 + 4 = 5.
so, x of D must be 5.
the y- difference of B to A is 3 (from 3 to 6). the y-difference from D to C must be the same (3). -5 + 3 = -2.
so, y of D must be -2.