[prewett]

I'd guess most of the places that use C would tend to be embedded; those that aren't probably moved to C++. Could you credibly claim to know C++?

Have you used Java or Python for anything in the past? If you need something now those are options with a lot of jobs.

If you only know C, I'd recommend at least learning Python. You'll use it for a lot of quick stuff, and it opens you to more jobs. If you want employment and are okay with "boring" companies, Java is useful: there are a lot of Java jobs that aren't going to go anywhere, and Java is superset of C so at least you'll get going quickly.

You can also go the contractor route, via Toptal, for instance. Breadth is also valuable in contracting. I got a contract once because I'd worked with the PostScript language a bit as a kid, so I could claim to have worked with PostScript.

If you can credibly claim to have learned multiple languages, you could try applying for an job with a fairly obscure language. If I were a hiring manager, I would assume anyone comfortable with C would be able to pick up the language my team is working on, and if you have other skills the obscure language shop might accept that nobody knows the language so they will have to train anybody they hire.