Two coherent monochromatic light beams of intensities 16I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are -

20I and I 36I and 4I 20I and 12I 36I and I

36I and 4I

$ I_{max} = (\sqrt{I_1}+ \sqrt{I_2})^2 = (\sqrt{16I}+ \sqrt{4I})^2 = 36I$ $ I_{min} = (\sqrt{I_1}- \sqrt{I_2})^2 = (\sqrt{16I}- \sqrt{4I})^2 = 4I$