Domain-wise backlinks: one URL to link or many

Hi all,

I was thinking what would be the best:
- a.) to place a domain-wise backlink on a domain, pointing to my main page (so 1 link per domain, n to 1)
- b.) to build a script what shows randomly a backlink on each page, from a set defined (n to n randomly)
- c.) to assign a backlink to each page the domain has and to place different links on each page, but keeping the same link on a given page (still n to n but not randomly).

Please share your thoughts.

 

plze specify your question to get it more detailed and easily answarable.

 

The question is pretty easy, which one to choose - a, b or c?

 

Could you please explain in more details?