SC gurus , please explain the correct answer :
Some patients who do not respond therapies of depression may simply have received inadequate treatment, having, for example been prescribed a drug as a dosage too low to be effective or having been
taken off a drug too soon.
A) having, for example been prescribed a drug as a dosage too low to be effective or having been
B) having, for example, a drug prescription that was ineffective because the dosage was too low, or being
C) as, for example, having too low of a dosage of prescribed drug for it to be effective, or being
D) when they have, for example, been prescribed too low a drug dosage for it to be effective, or were
E ) for example, when they have a drug prescription with a dosage too low to be effective, or been
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