Rectangles have two properties that are not included in the definition. the opposite sides of a rectangle are always of equal length, and the opposite sides of a rectangle are always parallel. why can't these two properties define a rectangle? chose the right answers.

a. a rhombus is also a quadrilateral whose opposite sides are parallel and equal in length.

b. the two opposite-side properties can be an alternate way to define a rectangle.

c. only some rectangles have congruent and parallel opposite sides.

d. the two properties are biconditional, and a definition cannot be biconditional.