The correct answer is option 2: About 65 million years. This is the estimated duration of time since the dinosaurs went extinct. The extinction event that wiped out the dinosaurs is known as the Cretaceous-Paleogene (K-Pg) extinction event, which occurred at the end of the Cretaceous period. This event is believed to have been caused by a combination of factors, including a large asteroid impact, volcanic activity, and climate change. These events led to widespread environmental changes that the dinosaurs were unable to adapt to, resulting in their extinction. Fossil records and scientific research indicate that dinosaurs roamed the Earth for approximately 165 million years before their disappearance. Therefore, it is estimated that they have been extinct for around 65 million years.