I'm so confused about this... please help me.
This is a sentence correction question from the SAT:
Giraffes born with very long necks were able to stay alive when food was scarce, __________________.
Which phrase best completes the sentence?
A. and were therefore able to pass this desirable trait on to their offspring
B. and this desirable trait was passed on as a result to its offspring
C. so that their offspring could have this desirable trait passed to them
D. so, therefore, this desirable trait would be inherited by their offspring
E. and therefore have this desirable trait inherited in their offspring
The answer is A, but I don't understand why C, E and B are wrong?