<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 23-year-old female presents to the emergency department with right lower abdominal pain that began suddenly one hour ago. She is writhing in discomfort and has vomited twice since arrival. She has no chronic medical conditions, but states she has had chlamydia two or three times in the past. Her abdomen is firm, and she is guarding. Pelvic exam reveals blood pooling in the vagina and right adnexal tenderness. Her last menstrual period was 7 weeks ago. A pregnancy test is positive.Which of the following is an appropriate next step in diagnosis?? A: Transabdominal ultrasound., B: Dilation and curettage, C: Transvaginal ultrasound, D: Methotrexate and discharge with strict follow-up instructions., E: Exploratory laparotomy,  <response>: This is a case of a 23-year-old female with acute right lower abdominal pain, vomiting, and a positive pregnancy test. She has a history of chlamydia infections. On exam she has right adnexal tenderness, suggesting this could be an ectopic pregnancy or ovarian torsion. The question asks for the appropriate next diagnostic step. Choice A transabdominal ultrasound may not provide adequate visualization in early pregnancy. Choice B DC would be inappropriate without a clear diagnosis, and could harm an ectopic pregnancy. Choice D methotrexate would also be inappropriate without a clear diagnosis of ectopic pregnancy. Choice E exploratory laparotomy is too invasive as a first step. Choice C transvaginal ultrasound is the best option, as it allows detailed visualization of the uterus and adnexa to help distinguish between ectopic pregnancy vs. ovarian torsion.C: Transvaginal ultrasound 