Answer:
The right answer is ability
Step-by-step explanation:
Ability is the possession of talent, skill or proficiency in a particular area of thing by an individual. This skill could be acquired or be inherent though in latent stage in an individual.
In the case of John, his success in the creation of a good campaign for the new product in their company is as a result of his ability which he invested most of his time in in trying to review previous articles similar to what he was trying to solve.
The skill of being meticulous paid off leading to him coming up with a campaign that recieved good review.