Upvotes for anyone who can in spanish!

choose the sentence that is grammatically correct

question options:

voy comprar una camisa.

voy a comprar una camisa.

voy a compro una camisa.

ancient india is often called the harappan civilization because one of the ancient cities was called harappa. harappa was just one of 1500 cities in the indus river valley. another well-known city is called mohenjo-daro. historians estimate ancient india to be the biggest of all four early civilizations.