For the purposes of this question a household corresponds to a single residential address, while household size is the number of individuals living at that address. Say you conduct a simple random sample of individuals living in Vancouver. Those sampled are asked to report their household sizes. The sample average of household size will be:

A. systematically biased downwards as an estimator of the average size of Vancouver households.
B. sensible as an estimator of the average size of Vancouver households.
C. systematically biased upwards as an estimator of the average size of Vancouver households.