Question SPL - Sailplane Pilot License - Meteorology

The gliding weather report states environmental instability. At morning, dew covers gras and no thermals are presently active. What development can be expected for thermal activity? - SPL

Formation of dew prevents all thermal activity during the following day

With ongoing insolation and ground warming, thermal lifting is likely to begin

Environmental instability prevents air from being lifted and no thermals will be generated

After sunset and formation of a ground-level inversion thermal activity is likely to begin