In the modern world, the two main forms of democracies are А
apartheid and confederal democracies.
B
presidential and confederal democracies.
О
c. apartheid and parliamentary democracies.
D
presidential and parliamentary democracies.

Democracies fall into two basic categories, direct and representative. In a direct democracy, citizens, without the intermediary of elected or appointed officials, can participate in making public decisions.

a and c?

i think it is a and c