Solve the equation and check for extraneous solutions. 7x=21 Submit test point(s) possible Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice. OA. The solution(s) is/are x = (Simplify your answer. Type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) OB. There is no solution.