Suppose that a state constitution contained the following statement regarding voting. "In order to vote in this state, eligible voters must register to vote in their county of residence, no later than September 1st of the election year."

Based on this information, which of the following statements are true?

a
Unless you register first, you cannot vote
b
You cannot register to vote after September 1st
c
You can only register in the county in which you live
d
All of the above