Commerce is a.
an official declaration that formally states a group's opinion or intentions
b.
the name given to taxes on the import and export of goods and commodities
c.
an incident where two sides disagree in a small argument or fight.
d.
the buying and selling of goods that takes place between two groups, especially countries.

The correct answer is b

Assemblies do not have written codes of laws. laws are matters for magistrates and courts, not assemblies. codes of law are things such as civil law, criminal law, and constitutional law. what assemblies have are procedures regarding debating, voting and other business they might carry out.  also note that rome had three assemblies: the assembly of the soldiers, the assembly of the tribes, and the plebeian councils.