Answer:
1. C.) careers page
2. C.) address it to
Step-by-step explanation:
The career page on a company's website shows information related to the company, how it is to work there, the profiles that they look for and the job opportunities that they have available. So, if you know the organization where you want to work, checking this page will give you an opportunity to get a better idea of what you should do to get the chance to work there.
In the other part, if you are going to write a letter, it would be better if you can find out who to address it to in the company as it would be good if it seems that you took the time to do the homework and the company will feel that you are really interested in working there.