Special sessions of Congress

(a) are called by the President to deal with some emergency situation.
(b) are called whenever a senator filibusters.
(c) are never called.
(d) are used to handle the everyday business of Congress.

(A) are called by the President to deal with some emergency situation

Example: The panic of 1893 there was a special session of congress called to deal with the crisis. Grover Cleveland was the President at the time. For any other everyday ordinary event, special sessions are not called.

they usually pass federal laws

and sometimes in the elections of the president