Ascertaining whether or not a regressor is strictly exogenous or exogenous ultimately requires all of the following with the exception of

Most tariffs around the world are collected on an ad valorem basis

Indicate whether the statement is true or false

Saying the consumer is rational means

A) the consumer is a stand-in for all consumers. B) the consumer is getting rationed. C) the consumer makes reasonable choices. D) the consumer makes the best choices.