a. True
In the statement, it is mentioned that at a Blood Alcohol Level (BAL) of .08, impairment is presumed. This implies that a person is considered impaired if their BAL is at or above .08. Additionally, the statement mentions that in Florida, a driver can be convicted of driving under the influence if their BAL is below .08 if it can be proven that they were impaired. This means that even if the BAL is below .08, the driver can still be convicted if impairment is proven. Therefore, the statement is true.