Question SPL - Sailplane Pilot License - Meteorology

The term "trigger temperature" is defined as the temperature which... - SPL

Is reached by a thermal lift during ascend when formation of Cumulus clouds begins.

Is the maximum temperature at ground level that can be reached without formation of a thunderstorm from a Cumulus cloud.

Is the minimum temperature at ground level that has to be reached so formation of a thunderstorm from a Cumulus cloud can occur.

Must be obtained at ground level so Cumulus clouds can be formed by thermal lifts.