It is a simple sentence.
A simple sentence contains one independent clause - which is the case with sentence 7. There is one subject (they) and one verb (rule), which means that it is a simple sentence (because of one verb only). A dependent clause wouldn't be able to stand on its own, and sentence 7 obviously can, which is why it is not dependent.
Answer && Explanation:
Choose answer choice A.
-Although many still claim that evidence about year-round school and its link to higher achievement is inconclusive, studies consistently reveal that year-round students score higher on certain assessments than those students who attend schools with traditional nine-month calendars.
provides a subtle way of telling off the skeptics. studies consistently reveal otherwise, and debunk the claims.
rest of the choices are too rude/aggressive.
If you accept either C or D as the correct revision then you have to accept both of them. Hence the best way to treat the sentence is to ignore both of them.
B is not correct either. You can over punctuate.
That leaves A.
Sometimes the right answer to many things is to do nothing. My dad used to say "Don't fix what isn't broke."
A is the answer <<<<<
