I think you may have forgotten an option. An affix placed before a word or base is called prefix.
I believe it's C but I would recommend getting a second opinion as I am just going by what makes the most sense. The other options go by looks which cannot always be accurate. Hope this helps! :D
Answer:
1. I don't see nothing wrong
2.Heard
3.Met
4.been waiting
5. even
6.plans and too
7.considering
