Final answer:
Lucius Malfoy's wand core is Dragon Heartstring, a material known for its strength and potential for powerful magic, fitting for his character.
Step-by-step explanation:
The core of Lucius Malfoy's wand is B) Dragon Heartstring. Wand cores in the Harry Potter series are known for their magical properties and their connection to the wielder's ability and personality. Dragon heartstring is a powerful wand core known for its strength and the potential for powerful magic, which aligns well with Lucius Malfoy's character as portrayed in the series. In contrast, phoenix feather and unicorn hair are cores that are typically associated with wands that have a particular affinity for good, whereas veela hair, another rare option, is known for its enchanting and temperamental qualities.