If you could get an in-bound link from anywhere on a target site, what is the best scenario?
IMHO the best place will be a contextual link on a homepage. Attention! Not in footer, sidebar or header....try to get it into content of the page.
Mhh i would consider Option A or Option C, i would prefer option A because i've seen a webdesigner in the past which added his "Webdesign: Company name" on every customers website he had ( in the footer )... eventually he was removed from the SERP's and he didn't do anything wrong.... So i'm always a bit careful with option C... I also wondered if it was because of that technique or he also had a ton of bad back links coming in...
the best way is link from the home page
Why? A brief statement like that without any reasoning to back it up isn't very helpful.
I would go for number 2. The reason is the relevancy. Number 1 can be good in terms of link value, but as per penguin, it would be much better to opt into a more relevant and targeted pages that deliver targeted traffic to your site.
Hope that helps!