The obvious jump is hobbled
A horse's jump dies on the square beside it: if the first step of the 日 is occupied — by ANY piece, friend or foe — the leg is hobbled (蹩马腿). Your own c5 pawn kills the jump to b6, exactly where a black horse sits. But the black horse on d2 is reachable — its leg at c3 is clear. Take the one that works.