12. Consider the following statements: (1) Magnetic field lines are always closed in the absence of magnetic monopoles. (2) The index of refraction n of a given material is defined as n = v/c, where v is the velocity of light in the material and c is that in vacuum. (3) Brewster's angle is the angle of incidence at which total reflection happens for a certain polarization. (4) It is possible that the phase velocity of electromagnetic waves in a material is larger than the velocity of light in vacuum. Which of the statements above are correct ? (A) (1), (2) and (3) are correct. (B) (1), (3) and (4) are correct. (C) Only (2) and (4) are correct. (D) Only (1) and (4) are correct.