C is the correct answer. the daily times article
I'm not too sure about this. However, I would say that it is Ok to say attached is the assignment. It seems wrong, but to make it seem more natural, maybe try adding extra words like requested.
Answer:
a
"although i had not stopped for beth" is a dependent clause
"she kindly stopped me" is an independent clause
commas help connect an indep. and dep. clause
hope that helps!
