What term is used for ‘style of writing’?

The correct answer is Option (1) → Palaeography

Palaeography is the study of styles of writing. The way letters were written changed over time: the letter ‘a’ was written one way in c. 250 BCE and another way by c. 500 CE. So an inscription that carries no date can often be dated quite precisely from the style of its letters.

The other options are related words: an inscription is a writing engraved on stone, metal or pottery; a script is a set of written signs, such as Brahmi; an epic is a long poem, such as the Mahabharata.