Which of the following features do zines and blogs share? a. both can cover any subject. b. both encourage comments. c. both are physical objects. d. both have large audiences.

The answer is A.Both can cover any subject. 
Zines differ from blog however they share common things such as the answer to the question and the ones below: 
1. Self-published and the publisher doesn’t  have to respond to anyone2. Small and self-distributed print run3. Motivated by the desire to express oneself rather than to make money4. Outside the mainstream5. Low budget6. Special equipment or knowledge is not required7. Portable8. An expression of Do It Yourself (DIY) cultureFoster a community among their creators and readers

The correct answer is c. maybe