Commenter bybe has it right - the best anchor text for your company is your company name. This is especially true if you're using it as part of a pro-active campaign to build backlinks, or if it's going to be reused programmatically.
The common use case for web design companies is attributing their work. Lots of web design companies put links on sites they've built back to their own domain. As the number of domains grow, and the number of pages on those domains grow, you end up with LOTS of repeated anchor text.
If that repeated anchor text is your company name, that's fine.
If that repeated anchor text is "keyword rich" (and all your examples A, B & C qualify), then you put your domain at risk of penalization for manipulative linking.
<a href="http://www.companyA.com">Company Name</a>
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