Assertion: In nineteenth-century European scholars were very excited when they discovered images of the Buddha and Bodhisattvas.
Reason: Images of the Buddha and Bodhisattvas were considered by them to be based on Greek models.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

When European scholars of the nineteenth century encountered sculptures of gods and goddesses from ancient India, they found them unfamiliar and puzzling. The presence of grotesque figures, with multiple arms, heads, or combinations of human and animal forms, often left them horrified.

In their attempts to comprehend these enigmatic images, these early scholars compared them to the sculptures they were more familiar with, particularly those from ancient Greece. Although they perceived early Indian sculpture as inferior to Greek art, they were captivated when they discovered Buddha and Bodhisattva images clearly influenced by Greek models. These Indo-Greek inspired statues were primarily found in the northwest, in cities like Taxila and Peshawar, where Indo-Greek rulers had established kingdoms in the second century BCE. Because these images closely resembled the Greek statues they knew, they were considered the finest examples of early Indian art.

This approach employed by the scholars - devising yardsticks based on what was familiar to make sense of the unfamiliar - is a strategy that we frequently use when encountering new and different things.