What does the word in bold "they" in the second paragraph refer to?

"Roger, remember that you won't be able to cancel the contract __________.”

These fish live _________ small sea creatures such as the shrimps. 

The gardener told me that everything __________ by the end of the year.

I'll give you some _______ of advice that can help you escape from the trouble.

Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks. 

     People all around the world are more and more associated with social networking, (5) _____ is a useful tool for those in the digital era. Social networking aims at promoting and aiding communication. (6) _____, this type of technology may be doing more (7) _____ than good. It is not only changing how we communicate, but how we associate with each other in everyday life. Sarah Zay, of USA Today, expressed that “With the growth of websites such as Facebook, social networking may be (8) _____ of replacing traditional personal interactions for the future generation”. Traditional interactions will continue to be at risk if we don’t (9) _____ the impacts of our social media. Social networking affects our lives in many ways, including our communication, self-expression, bullying, isolations, companionships, and even our very own sense of humanity.