17.
Your Answer is
Correct Answer is B
Explanation
According to the meaning of the sentence, it means "Hawaii became a state in 1959". Item B indicates that the preceding and following events occur simultaneously.
A item to become expresses the purpose, and the logic is wrong.
The attributive clause in item C modifies Hawaii. Since Hawaii is very clear, it is only right to use a non-limiting attributive clause here.
D item becoming means that it is becoming, this action is not continuous, so it is wrong.