Sentence Correction

According to a recent study, the decrease in percentage of citizens with obesity so that is was the lowest in a decade suggests that public awareness campaigns and good health initiatives may be paying off.
Choices
A - so that is was the lowest in a decade
B - so in being the lowest in a decade
C - to the lowest level in a decade
D - to what would be the lowest in a decade
E - to a decade-low level

Can someone please explain this question?

OA : C

According to a recent study, the decrease in percentage of citizens with obesity so that is was the lowest in a decade suggests that public awareness campaigns and good health initiatives may be paying off.

Choices

A - so that is was the lowest in a decade
B - so in being the lowest in a decade
C - to the lowest level in a decade- Perfect
D - to what would be the lowest in a decade
E - to a decade-low level - Ambiguous

What is the source of the Question , just out of curiosity.

happymanocha wrote:According to a recent study, the decrease in percentage of citizens with obesity so that is was the lowest in a decade suggests that public awareness campaigns and good health initiatives may be paying off.
Choices
A - so that is was the lowest in a decade
B - so in being the lowest in a decade
C - to the lowest level in a decade
D - to what would be the lowest in a decade
E - to a decade-low level

Can someone please explain this question?

OA : C

Source : Grockit.

So that is used to show causal relationship.
He went there so that he would get the best deal.
Two sentences-
He went there.
He would get the best deal.

to check -
he would get the best deal, because he went there.

A) no use of "so that" , because no causal relationship is expressed.
B) very awkward
C) best sentence
D) unnecessary use of "What". Try to avoid unnecessary use of what.
E) decade-low is not good word for informal writing.