TherapieGo: If Q19 works, it's only because the outside is not solid and so O19 is Sente but if that's the case then we must also say that T16 has the right to be sente and so if that's the case we can live unconditionally !?
posetcay: Marked R18 as wrong as it leads to approach ko. Q19 leads technically leads to direct ko but it is significantly inferior to P19 so I am tempted to mark it as wrong also. If we decided to keep it as an answer, we should also add O19 as first move as well since it leads to the same shape.
Yeah, it doesn't make sense to accept D1 as an answer when E1 is the proper shape here.