“Remorse” means deep regret or guilt for a wrong committed, hence option B is the correct answer because it means feeling guilty.
Option A is incorrect because “reparation” means the action of making amends for a wrong one has done, which means reparation follows after remorse usually, hence incorrect.
Option C is incorrect because “recuperation” means recovery from illness or exertion, hence it is incorrect.
Option D is incorrect because “regulgence” means to shine brightly or radiate bright light, hence it is incorrect.