Sentence Correction

Clark and Florence Wallace, a husband-and-wife medical team, worked steadily and efficiently through the night, but sipping their coffee the next morning, she noticed that he seemed disoriented.

(A) sipping their coffee the next morning, she noticed that he seemed disoriented
(B) sipping their coffee the next morning, he seemed to be disoriented, she noticed
(C) as they sipped their coffee the next morning, she noticed that he seemed disoriented
(D) as they were sipping their coffee the next morning, he seemed, she noticed, disoriented
(E) he seemed disoriented, she noticed, sipping their coffee the next morning

OA is c

B D E look awkward.

C maintains the parallelism in the past tense.

Sipping breaks the past tense.

A, B - dangling modifier
D, E - run on sentence

C - correct

did C change the meaning of the original sentence...

I chose A. From the earlier responses, i dont understand how it is the case of dangling modifier.

Plz explain.