Find all real numbers in the interval (0,2x] that satisfy the equation 5 cos (3x)-5 cos (x) = 0 Select the correct choice below and, if necessary, fill in the answer box to complete your choice OA. The solution set is {} (Simplify your answer Type an exact answer, using x as needed. Use integers or fractions for any numbers in the expression Use a comma to separate answers as needed) B. The solution set is the empty set. .