The correct answer is B) prevents fraying of the bitter end. Whipping the bitter end (the final part) of a fiber rope is done to prevent the individual strands from unraveling or fraying. This helps maintain the integrity and strength of the rope, which is important for safety and proper functioning. The whipping secures the end of the rope, keeping it from becoming frayed or damaged. The other options are incorrect because: A) making handling easier is not the primary purpose, C) preventing moisture is not the main reason, and D) increasing the circumference is not what whipping accomplishes.