Group 1 lists countries that DO NOT need a tourism visa to enter Bolivia.
Group 2 lists countries that DO need a tourist visa but DO NOT need to get it in the country of origin via a Bolivian consulate (you can get it at border points or an airport immigration point upon arrival). Singapore belongs to this category.
Group 3 lists countries that DO need a tourist visa and DO NEED to get it in the country of origin by way of a Bolivian consulate BEFORE you arrive in Bolivia