Hey there!
Your answer is B. Intramolecular; intermolecular.
Intramolecular forces are the forces that keep the atoms together in the molecule.
Intermolecular forces are the forces that are different molecules interacting with each other.
You can remember this by thinking about the prefixes inter- and intra-. Inter- refers to open systems within groups. The groups are the different molecules which are interacting with each other.
Intra-, however, refers to the closed system inside of a single group. The single group is the one molecule, and the interactions are happening between the atoms within the molecule.
Hope this helps!
