Answer: The correct options are (a) congruent and (d) intersecting.
Step-by-step explanation: We are to select the correct options that best describes the diagonals of a rectangle.
RECTANGLE: A rectangle is a quadrilateral in which
(i) the adjacent sides are perpendicular,
(ii) opposite sides are parallel and congruent,
(iii) Each angle is a right angle,
(iv) The diagonals are congruent and bisect each other.
For example, in the attached figure, ABCD is a rectangle.
The diagonals AC and BD are congruent and they intersect at the point 'O' such that AO = OC, BO = OD.
Therefore, the diagonals of a rectangle are congruent and intersecting.
Thus, the correct options are (a) and (d).