Answer:
C. An external downward field is created or an external downward field is removed
Explanation:
As we can see that from the attached figure that the induced current would be counter clockwise. So the field occur because of induced current i.e. out of page. This represent that the current is induced in order to rise the flux out of the direction of the page
Therefore because of the external field, the field out of page & flux would be reducing or the external upward field is eliminated
So option C is correct