Answer: Addition to existing product line.
Since, the new product is a spicier version of its tomato ketchup aimed at the baby boomer market. But still it lie in accordance with the existing product line.
The product line denotes the unit of affiliated commodities all marketed under a single brand name which is further is sold by the same organization. Establishments sell several product lines under several brand names, looking to differentiate each other.
Therefore, the correct option is (d).