The attraction of M 1 to M2 and the attraction of M2 to M 1 are equal forces, so A is wrong.
Binary stars provide centripetal force through mutual attraction. If the angular velocity is equal and the period is equal, then B is correct.
Binary stars provide centripetal force through mutual attraction, and it can be known that the motion radius of binary stars is inversely proportional to their mass. Because M 1 > M2, the moving radius of M 1 is smaller than M2, so c is correct.
The running speed of binary stars shows that the running speed of binary stars is inversely proportional to their mass. D is wrong because the moving speed of M 1 > M2 and M 1 is less than M2.
So choose BC