The correct option is B ventricles
Chordae tendineae are the fibrous cords which are attached to the flaps of the bicuspid and tricuspid valves that are present in the left and right auriculoventricular foramen respectively.
The other end of the chordae tendineae is attached to the ventricular walls through special muscles called papillary muscles. So the chordae tendineae is only found in the ventricles.
These fibrous cords prevent the auriculoventricular (AV) valves from collapsing back into the atria during powerful ventricular contractions.
Auricles and pulmonary trunk do not have chordae tendineae though there are valves in the pulmonary trunk and inlets of the right atrium.