Two ideas compete for the same place. Decide which one would do more for the problem and what it says a good idea is, taking into account how likely each is to work, given its known weaknesses, and what it would cost to carry out. Originality is not a criterion. Do not prefer an idea because it is longer.

$frame

Idea A:
$a

Idea B:
$b

Return only JSON, with no other text. "winner" is "A" or "B", whichever idea wins:
{"winner": "...", "rationale": "One or two sentences."}
