Final answer:
The percentage of Canadian households consisting of adult couples and co-resident children is suggested to be around 30%, based on the paralleled family structure trends similar to other wealthy countries.
Step-by-step explanation:
When determining the percentage of Canadian households consisting of adult couples and co-resident children, we can look towards the statistics related to family structures in comparable societies. Based on the information provided, about 30% of 15-to-29 year-olds in Canada are living with their parents. This would suggest Option A: 30% might be close to the current state of Canadian households with adult couples and co-resident children. It's important to consider that family dynamics are changing globally with the increase in single-parent households, cohabiting parents, and the variation in nuclear families. This dynamic shift is also notable in Canadian society. For an accurate representation of Canadian numbers, one would need to consult the latest Canadian census data or a reliable national statistics database.