(B) Ability
An acquired or natural capacity that enables you to perform a particular task with considerable proficiency is termed as Ability.
The key phrase here is "acquired or natural capacity to perform a task with proficiency" — this directly defines Ability. Interest refers to liking for something; Hobby is a leisure activity; Weakness is a limitation. Examiners expect you to identify the correct option and briefly justify it in 1-mark MCQs.