Solve the equation for exact solutions over the interval [0, 2). 7 cos 2x + 14 cosx+7=0 Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA. The solution set is (Type an exact answer, using as needed. Type your answer in radians. Use integers or fractions for any numbers in the express Use a comma to separate answers as needed.) OB. The solution is the empty set.