Which of the following is a true statement?
a. the citizens of a state may only register to vote after proving to have submitted their census survey.
b. the census is a flawed tool because census workers do not attempt to count all citizens, just a sample.
c. the main purpose of conducting a census every 10 years is to determine representational apportionment.
d. the majority of apportionment changes are due to state-level data collection and not national census data.