This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'A male 45 years old wants his missing teeth to be replaced. Intraoral examination reveals Kennedy class 4 edentulous  maxillary arch. Impression is made with fast setting alginate.\nThe setting time of the material is : \nSelect and explain. \nA. 1.5 to 3 min, B. 3 to 4.5 min, C. 3 to 4 min, D. 2 to 4 min', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A slight modification in the W/P ratio or the mixing time can have marked effects on two important properties of the gel, tear\xa0 strength,\xa0 and\xa0 elasticity;\xa0 thus, the setting time is best regulated by the\xa0 amount of retarder added during\xa0 the\xa0 manufacturing\xa0 process.\xa0 Usually,\xa0 the\xa0 manufacturers\xa0 make both fast-setting alginate (1.5 to 3 min) and normal-setting alginate (3 to 4.5 min) to give clinicians a choice of the materials that best suit their working style.\nClinicians, however, can safely influence the setting time by altering the temperature of the water.\nKey Concept: Fast-setting alginate has a setting time of 1.5 to 3 min.', 'role': 'assistant'}]