Final answer:
The Jones family at 7:30 PM last night were most likely watching TV based on the cultural context of 1958, where families commonly gathered around the television and even had dinner while watching TV.
Step-by-step explanation:
The question 'What were the Jones family doing at 7:30 PM last night?' with options including 'Watching TV', 'Having dinner', 'Sleeping', and 'None of the above' refers to common activities that families might engage in during the evening. Based on the provided reference information, which describes an American family in 1958 relaxing in front of their television set and notes the marketing of small folding tray tables and frozen 'TV dinners', we can infer that it was common for families during that era to watch TV and potentially have dinner at the same time.
In the context of 1958, the Jones family at 7:30 PM were most likely watching TV and could have possibly been having their dinner in front of the TV as well. This reflects how the cultural norm of gathering around the television became a popular pastime, as also indicated by the popularity of folding tray tables and TV dinners of that time.
The answer to the question would therefore likely be 'a) Watching TV', with the possibility of 'b) Having dinner' occurring simultaneously if the family followed the cultural trends of the period.