Sentence Correction

121. As a result of medical advances, many people that might at one time have died as children of such infections as diphtheria, pneumonia, or rheumatic fever now live well into old age.
(A) that might at one time have died as children
(B) who might once have died in childhood
(C) that as children might once have died
(D) who in childhood might have at one time died
(E) who, when they were children, might at one time have died

OA is B

Can someone explain in detail ?

Eliminate answer choices A and C, the use of the word "that" is incorrect. The relative pronoun should be "who."

Between B, D, and E - solutions D and E both use the phrase "at one time died." This phrase changes the original meaning of the sentence because it can be interpreted that children died at one time and were perhaps revived.

Only answer B retains the logical meaning of the original sentence. I would say the word "once" is more concise than "at one time" as well.