Answer: The correct answer is A: Changing the relative evaluation of attributes associating the product with a special group, event or cause.
Explanation:
The company here associates its product (Diet coke) with an event or cause called the American Heart Association.
This association will move people that want to adopt healthy habits such as Tom wanting to cut the carbohydrates out of his diet, to buy their products because the evaluation of the attributes of the product changed.
In conclusion, the strategy that the company used is: A, Changing the relative evaluation of attributes associating the product with a special group, event or cause.