7. If one of the two slits in a Young's double-slit demonstration of the interference of light is covered with a thin filter that transmits only half the light intensity, which of the following occurs?
(A) The bright lines are brighter and the dark lines are darker.
(B) The bright lines and the dark lines are all darker.
(C) The bright lines and the dark lines are all brighter.
(D) The dark lines are brighter and the bright lines are darker.