A) Historians are as employable as anything else if you're good.
This is correct, and a very underrated point! It depends a bit on which country you live in of course. But when you study history, you don't only learn about history (in fact that is sort of just a side effect). You also and mainly learn to work academically, to be structured in your way of thinking and approaching problems, and to think critically and be reflective of different standpoints. This is true of the humanities in general, but at least in Germany where I am from, history is commonly viewed as the humanity which is the most demanding regarding academic skills.
Having obtained these skills, wide fields of employment are open to you, which don't necessarily have to have anything to do with history at all. A friend of mine who studied history with me works for Airbus now, in their archives, which he finds extremely interesting (and it's very well paid!). Another has become a fund raiser, yet another is a journalist, while I have become a teacher; my job having the closest connection to history of the four, yet not exactly prototypical of a "historian's" job. A few of my former fellow students have got more classical historian's jobs, i.e. pursuing a uni career or doing historical research in other institutions, but they are definitely more the exception than the rule.
So I have to agree vividly with jj that you shouldn't choose your degree based on the assumption of employment opportunities, but instead on what you want to do, and on what you can bring up enough interest for to obtain a certain amount of quality and passion. The rest will follow suit.