Match List I (Compound) with List II (Nature) and select the correct answer using the code given below the Lists:

              A            B             C             D

(a)          2             3             4             1

(b)          2             4             3             1

(c)          1             4             3             2

(d)          1             3             4             2

a) a
b) b
c) c
d) d