SC2

[leo]

Using a Doppler ultrasound device, fetal heartbeats can be detected by the twelfth week of pregnancy.
(A) Using a Doppler ultrasound device, fetal heartbearts 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 twelfteh week of pregnancy, a physician can use a Doppler ultrasound device.
(D) By the twelfth week of pregnancy, fetal heart-beats 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.

Answer Please and why

[jayhawk2001]

Using a Doppler ultrasound device, fetal heartbeats can be detected by the twelfth week of pregnancy.
(A) Using a Doppler ultrasound device, fetal heartbearts 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 twelfteh week of pregnancy, a physician can use a Doppler ultrasound device.
(D) By the twelfth week of pregnancy, fetal heart-beats 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.

Answer Please and why

E? We have a dangling modifier here...

A - using a Doppler incorrectly modifies fetal heartbeats
B - unnecessary passive voice, missing main subject
C - awkward
D - awkward use of passive voice again

[discreet]

Using a Doppler ultrasound device,fetal heartbeats can be detected ....

Here the modifier "using a doppler ultrasound device" is describing a physician who detected the fetal hearbeats.In the sentence,the phrase seems to modify the fetal hearbeats.This is incorrect.The fetal heartbeats did not use the doppler ultrasound device.Hence,you must insert a noun which the modifier can modify.
This error is known as dangling modifier error.

One more vote for E...

[hemanth28]

how about a choice B.
the clause "using a doppler ultrasound device " looks like a adverbial modifier ,modifying the verb detected.can someone please let me know if i am wrong and why am i wrong!!

So this makes both B and E as right options.

[Stuart@KaplanGMAT]

This particular error is one of the VERY rare times that the correct answer to a SC question will introduce something new.

The big problem with most of the choices is that they're written in the passive voice - there isn't anyone/anything in the sentence that's actually DOING the action. We need someone/something to use the device, otherwise there's nothing for "using a .. device" to modify.

Only (E) fixes the voice and modification issues without adding new problems.