Answer:
2) at least one multiple carbon-carbon bond.
Step-by-step explanation:
- An unsaturated hydrocarbon must have a double or triple C-C bond which is unsaturated bond that means it is not saturated with atoms.
- Saturated hydrocarbon is the hydrocarbon in which all C-C bonds are single.
So, A molecule of an unsaturated hydrocarbon must have 2) at least one multiple carbon-carbon bond.