A 50-year-old male presented to the ER with acute onset of chest pain which was retrosternal and radiated to the back along with dysphagia, regurgitation and heaburn. Patient gave history of similar episodes of chest pain in the past as well. Barium swallow and esophageal manometric studies were performed. ECG of the patient was normal. Manometry study revealed, 1. Aperistalsis in greater than 30% of the wet swallows with 20% of contractions being simultaneous 2. Amplitudes greater than 30 mm Hg in the distal three fifths of the esophagus Which of the following drugs can be used in the above condition to relieve the symptoms: –