Sentence Correction

Some patients who do not respond to 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

Hi Mitch!

This question is giving me hard time. Can you please help me with the same. For some reason, comma+having usage has always troubled me.

Regards
SR

Yes, it's an interesting question that has caused many people problems. As you have said, you have challenges with the , having clause.

Really, it's just a way to join two sentences. Here we have two sentences:

Mary has finished her homework.
Mary is going to the party.

We can combine these two sentences into: Mary, having finished her homework, is going to the party.

Here's a similar question:

Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about how the human brain grows and how babies acquire language.

(A)Neuroscientists, having amassed a wealth of knowledge over the past twenty years about how the human brain and its development from birth to adulthood, are
(B)Neuroscientists, having amassed a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
(C)Neuroscientists amassing a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
(D)Neuroscientists have amassed a wealth of knowledge over past twenty years about the brain and its development from birth to adulthood,
(E) Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood,
==============================================
The first sentence is really just two sentences combined:

Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood.
Neuroscientists are now drawing solid conclusions about how the human brain grows and how babies acquire language.

P.S. Part of your problem may be that the first answer choice seems incorrectly typed. I believe that it should say "prescribed a drug at a dosage too low to be effective..."

Thank you very much for the explanation.
I can understand the examples you gave, but still struggling about the original problem. Can you help to explain the original problem? Thanks in advance.