Which statement is true about conjunctions?

they should be used to combine two or more long sentences.

they are used to make sentences shorter.

they should not be used in essays.

they are often used to combine choppy sentences

The answer is:  [D]:  


They are often used to combine choppy sentences.
   
     Conjunctions are often used to combine choppy sentences.

Note:  The questions asks about CONJUNCTIONS —NOT about "contractions".

Choice "A" is incorrect.  They are not used to combine two or more LONG sentences.  If sentences are already long, then do not need to be combined with a conjunction.

Choice: "B" is incorrect.  To the contrary, the use of conjunctions actually makes sentences longer.

Choice "C" is incorrect.  To the contrary, the use of conjunctions should be used (appropriately, of course) in essays.  The use of "contractions" should not be used in essays or formal writing.

Choice "D" is correct.  They are often used to combine choppy sentences for better reading and engagement.