Match the items of List-I with those in List-II and select the correct answer.

List-I	List-II
a. Bank Rate Policy	1. Involving the shortening of the currency of bills eligible for rediscount.
b. Credit Rationing	2. Involving the purchase and sale of securities in the open market.
c. Variable Reserve System	3. Involving the alteration of discount rate.
d. Open Market Operations	4. Involving the Variation of the minimum reserve.