<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 27-year-old woman comes to the physician because of a 1-month history of progressive shortness of breath. She can no longer walk one block without stopping to catch her breath. Her last menstrual period was 3 months ago. Menarche occurred at the age of 12 years, and menses had occurred at regular 28-day intervals. Cardiac examination shows a grade 36, rumbling diastolic murmur at the apex. Laboratory studies show an elevated β-hCG concentration. Which of the following is the most likely explanation for this patients worsening dyspnea?? A: Increased peripheral vascular resistance, B: Decreased right ventricular preload, C: Decreased minute ventilation, D: Increased intravascular volume, E: Increased right ventricular afterload,  <response>: This is a patient with a 1-month history of progressive shortness of breath and a 3-month-old pregnancy, as evidenced by the last menstrual period 3 months ago and elevated β-hCG. The murmur and pregnancy help narrow down the likely cause of her dyspnea. During pregnancy, the increased circulating blood volume leads to increased preload on the heart. This causes eccentric hypertrophy of the heart chambers, particularly the left ventricle, in order to accommodate the increased volume. The increased preload also leads to increased stroke volume. However, the remodeling of the heart chambers causes a decrease in compliance, leading to an increase in filling pressures. The increased blood volume and cardiac output also leads to increased pulmonary blood flow and pulmonary pressures. Together, these hemodynamic changes in pregnancy can result in exertional dyspnea. Of the choices given, increased intravascular volume best explains this patients worsening dyspnea in the setting of pregnancy.D: Increased intravascular volume 