Doppler effect

[lav]

Using a Doppler ultrasound device, fetal heartbeats can be detected by the twelfth week of pregnancy.
(A) Using a Doppler ultrasound device, fetal heart-beats can be detected by the twelfth week of pregnancy.
(B) Fetal heartbeats can be detected by the twelfth week of pregnancy, using a Doppler ultrasound device.
(C) Detecting fetal heartbeats by the twelfth week of pregnancy, a physician can use a Doppler ultrasound device.
(D) By the twelfth week of pregnancy, fetal heartbeats can be detected using a Doppler ultrasound device by a physician.
(E) Using a Doppler ultrasound device, a physician can detect fetal heartbeats by the twelfth week of pregnancy.

OA is E
Why is D wrong ? What changes should i make to it to make it correct ??

i choose the correct answer i am just inquisitive that why is D wrong

[Vemuri]

The original sentence has a modifier issue. Who is using the Doppler ultrasound device?

As for D, the sentence is in passive voice. That's why E is preferable to D.

[maverick2000]

D has passive voice and awkward construction. In E, first of all subject is added and secondly, it is close to the modifier. So E is more appropriate.