Answer:
It's D
Explanation: (To summarize)
I think that people believed that processed foods made life easier,in the 1950's and that is why it became the Golden Age of Food Processing. Foods like chicken pies or frozen fruit or vegetables or canned goods were fast and easy to prepare and with the stress of modern life of working and looking after a family there was less time for from scratch food preparation.
B. is the correct sentence, because they use the correct verb tense of notices.