Starting from the year 0, [I] might be able to advance civilzation to the 17th or even 19th century. [I am] technologically useful.

I scored 7 out of 10 on the ‘If I were sent back to the year 0 how technologically useful would I be?’ quiz (though slightly embarrassingly I’m not 100% sure which ones I got wrong), and as Jason says inventing new technologies isn’t multiple choice. And I’d probably succumb to the local equivalent of the common cold. Or inadvertently start a plague. Or be burnt as a witch.