Solution:Concept: The Mesozoic era is known as the "golden age" of reptiles.
The second of Earth's three main geologic eras during the Phanerozoic epoch is the Mesozoic Era. The term "middle life" in Greek is where the name of the era originates. Following the end of the Palaeozoic Era and the start of the Cenozoic Era, the Mesozoic epoch started about 252.2 million years ago. Therefore the Golden age of reptiles was the Mesozoic era.
Hence, option 3 is the correct answer.