Hm, I personally found shell scripting very frustrating.
Out of the 2), I'd pick Ruby. Feels the most newbie-friendly.
C? Hm, yes, maybe. But I doubt you can manage C in 8 months if you never coded before. And for a "startup engineer", it might not be that relevant anyway.
I don't understand the mystique surrounding C. If you forget about pointers and structs for a minute and keep everything to one .c file and one .h file, there's nothing that would keep a beginner from learning the rest. Even though you can do complicated things with it, it's not that complicated of a language. Once a beginner learns to deal with "array index out of bounds" etc. they'll have a much easier time writing well-formed code in the future. C's role as an ancestor of (almost) all modern languages means that once you're familiar with it, new languages will be easier to pick up. Plus, the language has a great book: I'd tell a beginner to pick up Kernighan and Ritchie and read that.
You can learn CS 101-type C pretty quickly by eliminating pointers/structs/etc., but you won't be able to read/alter any real-world open source C. If you learn Python or Ruby, for example, you can jump into github and see what people are doing right now.
If you're looking for an ancestor language, you'd be just as well off learning Smalltalk, which you can do real things with immediately (e.g. learn it in the browser with Seaside), and then apply those lessons to modern languages like Obj-C and Ruby.
Out of the 2), I'd pick Ruby. Feels the most newbie-friendly.
C? Hm, yes, maybe. But I doubt you can manage C in 8 months if you never coded before. And for a "startup engineer", it might not be that relevant anyway.