Sentence Correction

Many entomologists say that campaigns to eradicate the fire ant in the United States have failed because the chemicals that were used were effective only in wiping out the ant's natural enemies, which made it easier for them to spread.

A. which made it easier for them
B. which makes it easier for it
C. thus making it easier for them
D. thus making it easier for the ant
E. thereby, it was made easier for the ant


I found this question on BTG. The OA is D. I would have chosen D, but I thought a conjunctive adverb such as "thus" should be followed by a comma. Hence, I selected E. I did see the split b/w "thereby" and "thus", and I also saw that E is wordier.

Am I wrong about the conjunctive adverb comma rule?

You are right that the Conjugative adevrb uses COMMA . But As the defination says. It is used to indicate the relationship in meaning between two independent clauses.

Here MAKING>....FOR ANT is not a clause.

tsharma wrote:Many entomologists say that campaigns to eradicate the fire ant in the United States have failed because the chemicals that were used were effective only in wiping out the ant's natural enemies, which made it easier for them to spread.

A. which made it easier for them
B. which makes it easier for it
C. thus making it easier for them
D. thus making it easier for the ant
E. thereby, it was made easier for the ant


I found this question on BTG. The OA is D. I would have chosen D, but I thought a conjunctive adverb such as "thus" should be followed by a comma. Hence, I selected E. I did see the split b/w "thereby" and "thus", and I also saw that E is wordier.

Am I wrong about the conjunctive adverb comma rule?

makes sense. thanx