In the Absence of Interstellar Dust, a Certain A0 Star

In the absence of interstellar dust, a certain A0 star has the same magnitude through a blue filter and through a visual filter. When the light passes through a dust cloud before being observed, the:

A) B and V magnitudes remain equal.
B) B magnitude will be a smaller number than the V magnitude.
C) V magnitude will be a smaller number than the B magnitude.
D) size of the dust particles will determine whether B or V is the larger number.