Aconcept map for four types of intermolecular forces and a certain type of bond is shown.

which of the following correctly identifies the intermolecular force represented by a and compares its strength relative to the intermolecular force represented by b?

a represents london dispersion forces, which are weaker than the force represented by b.
a represents hydrogen bonding, which is weaker than the force represented by b.
a represents london dispersion forces, which are stronger than the force represented by b.
a represents hydrogen bonding, which is stronger than the force represented by b.

A represents London dispersion forces, which are weaker than the force represented by B.

Explanation:

London Dispersion Forces : Intermolecular forces exist  between non-polar molecules.  They are very weak forces.  Thought to be arise from the  motion of electrons.

H-bonding: It is a special type of dipole-dipole interaction  between the H-atom in a polar bond such as N-H,  O-H, F-H and an electronegative atom such as  nitrogen, oxygen and fluorine.

It is clear that H-bonding is stronger than London-dispersion.

So, the right choice is:

A represents London dispersion forces, which are weaker than the force represented by B.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.