this example tests you on parallelism.
"than" requires parallelism. Also, note that "it" refers to "age of thirty".
"more babies were born to women over the age of thirty than under it." - Note that for parallelism, we start from right to left. See what is parallel to "under it" on the Left hand side of "than".
A maintains parallelism and hence is the correct answer. Since the sentence maintains parallelism what is implied here -
More babies were born to women over the age of thirty than [babies were born to women] under it.
B - Incorrect answer.
Answer option does not maintain parallelism. let us look at parallelism -
"more babies were born to women over the age of thirty than born under it.
Not perfectly parallel. "to women" is missing in RHS.
This answer option nonsensically implies that "[babies were] born under age of thirty".
C - Incorrect answer.
"more babies were born to women over the age of thirty than they were under it.". - two clauses are in parallel; however, "to women" is omitted. this changes the meaning of the sentence.
this sentence implies that babies were born under age of 30. - Illogical.
D - Incorrect.
Usage of past perfect is incorrect. We are referring to a specific time period - 1998.
Also, this option changes the meaning of the sentence.
E - Incorrect.
Usage of past perfect is incorrect. We are referring to a specific time period - 1998.
Changes the meaning of the sentence (like option B) -
"more babies were born to women over the age of thirty than had been born under it.
Not perfectly parallel. "to women" is missing in RHS.
This answer option nonsensically implies that "babies had been born under age of thirty".
