Answer:
a. preference
Step-by-step explanation:
As in the question it is mentioned that the heather Green normally purchased heinz Catsup as she likes the taste but she decided to purchase another brand i.e. highly advertised also it was on sale and she really needs it
So here the Heinz achieved the preference as usually she purchased the Catsup product but sh purchased another product due to high advertisement
So the preference is shifted to another product
Therefore option a is correct