Is this a probability or nonprobability sample?

You are an infectious disease expert interested in determining if administering tuberculosis (TB) treatment with a directly observed therapy (DOT) program has an impact on the risk of developing multiple-drug-resistant (MDR) tuberculosis. You randomly select 120 individuals newly diagnosed with TB and randomize them into two equal groups—one group receives treatment without DOT, and one group receives treatment with DOT. You follow the groups for 2 years and identify all cases of MDR TB that develop. You find that 2 of the individuals who receive treatment and DOT develop MDR TB, and 10 of the individuals who receive treatment without DOT develop MDR TB.