What is the main characteristic of an impost according to the Brazilian Tax Code (CTN)? a) It is a tribute whose obligation has a triggering event ...

What is the main characteristic of an impost according to the Brazilian Tax Code (CTN)?
a) It is a tribute whose obligation has a triggering event independent of any specific state activity related to the taxpayer.
b) It is a tribute whose obligation has a triggering event dependent on a specific state activity related to the taxpayer.
c) It is a tribute whose obligation has a triggering event dependent on a specific state activity related to the taxpayer, and it is always paid in currency.
d) It is a tribute whose obligation has a triggering event independent of any specific state activity related to the taxpayer, and it is always paid in currency.
I- The impost is a unilateral and non-linked tribute.
II- The impost is a linked tribute.
III- The impost is a tribute whose revenue is earmarked for specific purposes.
IV- The impost can only be instituted by the Union.