Number two. Why? Because there is more than one quarter; there are three quarters. One quarter = is. Three quarters = are. Most of the population + is. Everybody + is. Nobody + is. Most of the people + are. Some of the people + are. None + is = OK and none + are = OK, too. Why? Because it's none, it's zero; if it's nothing then everything is OK. Language is not science but there is some science to the grammar, especially when we are dealing with numbers.

2. Three quarters of the populace in this area "are" farmers.

number 2