Which option is better for the blank and why?Thanks?

'Could live' is by far the better option! It makes perfect sense...The girl could live abroad but because she would be far away from her parents she changed her mind! It is her free choice! 'Was to have lived' makes the reader believe that she was supposed to live abroad but decided not to! It gives the impression that she is making a wrong choice!!!

a, but change it to "could have lived," because her choice was in the past. Could is present, and she's already decided against it.

b is way wordier and mutates it into some obscene passive form!

"was to have lived" also subtly implies that she had no choice in the matter (someone decided that she was to live there) whereas the context at the end of the sentence (that she changed her mind) shows that a is better because it doesn't tell you whose decision it was.

Have a good night!

b - was to have lived

I don't know the specific verb tenses involved, but the answer has to do with matching the tenses in the sentence. To see which of the verb phrases fits better, you can simplify the sentence somewhat:

She COULD LIVE abroad, but something MADE HER CHANGE HER MIND.

She WAS TO HAVE LIVED abroad, but something MADE HER CHANGE HER MIND.

Does this make it easier to see?

B WAS TO HAVE LIVED for sure. Don't listen to the others. Could live does not make sense in this context. Trust me.

a. could live

a. could live

could live

wanted to live