<p>In 1777, when news reached Colonel Ludington that the town of Danbury, Connecticut, was being looted and burned by British troops, his daughter Sybil rode forty miles through the night so that the soldiers of her fathers regiment had been alerted to the danger.
(A) so that the soldiers of her father's regiment had been alerted
(B) so that the soldiers of her father's regiment may be alerted
(C) alerting the soldiers of her father's regiment
(D) and alerting the soldiers of her father's regiment
(E) for alerting the soldiers of her father's regiment</p>
<p>This is a question from online course. I don't really understand why it's C. I thought that comma must be used, if it's C. That's why I chose A.</p>
<p>"so they had been alerted" is in the wrong tense and makes no sense... the beginning of that phrase says "Sybil rode forty miles"..... put it together to make" "Sybil rode so they had been alerted" which makes no sense.</p>
<p>even if there was an option "So they could be alerted," it would be wrong because that complicated phrase can easily be replaced by "Alerting them" (choice C)... and remember we're choosing the best answer</p>