The canal of a maxillary canine has been instrumented to within 1mm of the apex and is ready to be obturated. A radiograph indicates that the master cone is 2.5mm short of the apex. The most appropriate management is to

discard the cone and fit a smaller one.

cut the cone 1mm and insert.

fit a larger cone within 2mm of the apex.

proceed with the filling as the cone is within acceptable limits.