<prompt> Which of the following evaluation methods is most sensitive in diagnosing pregnancy early?Serum pregnancy testDetection of fetal heart tones by Doppler equipmentAbdominal ultrasoundBimanual exam to assess uterine size  <response>: A Doppler instrument will detect fetal cardiac action usually no sooner than 10 weeks.A sensitive serum pregnancy test can detect placental HCG levels by 8 to 9 days post-ovulation, and it is therefore the most sensitive modality for detecting and diagnosing pregnancy. 