Help with Odden's task

[Matt Addison]

Hi everyone. I'm a beginner student of phonology and I'm stuck at the fourth exercise of David Odden's Introducing Phonology, chapter 4. It's about underlying representations.



I have such a difficult task with finding underlying representations and the only pattern which I seem to notice is the consonant voicing or devoicing depending on the suffix.
I came up with the following rule but I don't know if it's correct or if it covers the entire task:
C → voiced / _ voiced consonant

Could anyone lend me a hand with this?

[Daniel]

I'm sorry, but we won't do homework for you, and it is also a problem for future students/instructors if the answers are posted online.
If you have a content question, rather than a question about an answer to a problem, you can ask that here.