Doubt about usage of conjunctive adverb

[reachdeepaky]

In order to properly evaluate a patient’s state of mind and gain informed consent prior to surgery, a substantial period of time must be spent with the operating physician by the patient to become fully aware of the pros and cons of undergoing a surgical procedure.
A. SAME
B. the operating physician and the patient must spend a substantial amount of time together, thus ensuring full awareness of the pros and cons of undergoing the surgical procedure
C. the patient must spend a substantial amount of time with his or her operating physician, thus ensuring that he or she has been made fully aware of the pros and cons of undergoing the surgical procedure
D. the operating physician must spend a substantial amount of time with the patient, thus ensuring that the patient is fully aware of the pros and cons of accepting the undergoing procedure
E. the operating physician must ensure that he or she is fully aware of the pros and cons of undergoing a surgical procedure by spending a substantial amount of time with the patient

OA is D

Please explain why E is wrong.
I did not chose D because THUS is conjunctive adverb and as per Manahattan SC guide, a conjunctive adverb must be preceded by semicolon. if the answer were - "the operating physician must spend a substantial amount of time with the patient; thus ensuring......" , then it would be right.
Please explain

[tim]

E suggests a need to make the physician aware, not the patient, so it is clearly wrong. The rule that you suggest applies to D is completely wrong, as is your use of a semicolon. Take a look at the rule you thought you were using and see if you can identify how you are misapplying it here; if you can’t, reply back with more particulars about this rule - including the page of our book you found it on - and we can help you see what’s wrong with what you are doing..