As a teacher, i vote for A, APIs should be documented, giving a good name to a parameter is usually the first step.
I'm willing to consider starting with A, though I think we should admit that the most likely reaction if we do that is "you idiots got it wrong again, we waited 25 years for underscore, and you don't even let us do it in the most obvious places." So I don't think "do A and never do anything about method parameters" is going to fly, though it is potentially a reasonable incremental step on the way there to get people used to unnamed things.
