At the preparation stage for a 4.6 DO restoration, a brown, non-cavitated lesion is observed on the 4.7 mesial proximal surface. There is no evidence on a bitewing radiograph of a radiolucency extending into the dentin. What is the most appropriate management of the mesial surface of tooth 4.7?

Perform no operative treatment and apply fluoride.

Prepare the lesion with a ball diamond and restore with a flowable composite resin.

Prepare and restore with a mesio-occlusal slot resin modified glass ionomer.

Prepare and restore with a mesio-occlusal slot composite resin.