Answer:
B. these
Explanation:
I like her shoes, but these are more expensive than hers.
Think about demonstrative pronoun as when you're pointing your finger to indicate to others what object you're talking about: "THOSE shoes are nice, but THESE ones are more comfy". So, imagine yourself pointing with your finger and say "THIS is what I'm talking about!".
Options A, C and D indicate "possessive" pronouns, which are used to indicate things that are owned by a person.
