In order to increase voter turnout many states have implemented which of the following?
a. new voting machines
c. phone in voting
b. early ballot voting
d. created more polling places

To increase voter turnout many states have implemented early ballot voting or also increased the number of polling places - B and D. Both strategies have slightly increased the number of people who voted for different political options. They, however, didn't increase it by a large margin as there still are a lot of people who have not yet voted in their lives, despite being able to do so.