According to the map above, which of the following statements about tornado frequency in Oklahoma is true? a. All Oklahoma counties are equally at risk for tornado activity.
b. Oklahoma has received more tornadoes since 1950 than in the previous 50 years.
c. No Oklahoma county has had more than 100 tornadoes since 1950.
d. Every county in Oklahoma has had at least 10 tornadoes since 1950.