The correct answer is: a) 3 months
A usual resident is a person who usually lives in a particular place. This means that they have a home in that place and they live there most of the time. They may also have a home in another place, but they do not usually live there.
The concept of ‘Usual Resident’ in the Census is important because it helps to ensure that the census counts the right people. If the census counted everyone who was staying in a place on Census Day, it would include people who were only visiting or who were planning to move away soon. This would give an inaccurate picture of the population.
The 3-month rule is used to identify usual residents because it is a reasonable amount of time for someone to be living in a place before they are considered to be a resident. It is also a time period that is easy to remember and apply.
The other options are incorrect because they are not long enough periods of time to be considered usual residence. A person who has only been living in a place for 1 month is not likely to be considered a usual resident. A person who has been living in a place for 6 months or 9 months may be considered a usual resident, but it is not certain. A person who has been living in a place for 1 year is definitely considered a usual resident.