<prompt> Single best parameter to assess gestational age in first trimester?CRL Crown Rump LengthBPD Biparietal diameterHC Head CircumferenceFL Femur Length  <response>: Best parameter to assess gestational age- First trimester - CRL Crown Rump Length Second trimester - BPD Biparietal Diameter Third trimester - BPD Biparietal Diameter Best Overall - CRL Crown Rump Length 