Ans. is 'c' is Right lateral decubitus chest X-ray Most dependent recess of the pleura is the posterior costophrenic angle*.So in pleural effusion this recess would be filled earliest. But at least 100-200 ml of fluid would be required to fill this recess before it can be detected on a PA view.Therefore in cases of minimal pleural effusion the best method to detect it would be- Decubitus view with a horizontal beam.