List I		List II
a	Nitrococcus	i	Denitrification
b	Rhizobium	ii	Conversion of ammonia to nitrite
c	Thiobacillus	iii	Conversion of nitrite to nitrate
d	Nitrobacter	iv	Conversion of atmospheric nitrogen to ammonia

Choose the correct answer from options given below.
(A)
(a) - (ii) ,
(b) - (iv),
(c) - (i),
(d) - (iii)
(B)
(a) - (i) ,
(b) - (ii),
(c) - (iii),
(d) - (iv)
(C)
(a) - (iii) ,
(b) - (i),
(c) - (iv),
(d) - (ii)
(D)
(a) - (iv) ,
(b) - (iii),
(c) - (ii),
(d) - (i)