`CH_(3)-overset(CH_(3))overset(|)(CH)-NO_(2) underset(at 0^(@)C)overset(NaNO_(2)+H_(2)SO_(4))(rarr)(A)`. `(A)` is:
A. a.`(CH_(3))_(2)-CH-OH`
B. b.`(CH_(3))_(2)CH-N=N-Br`
C. c.`(CH_(3))_(2)underset(NO_(2))underset(|)(C)-N=O`
D. d.`(CH_(3))_(2)underset(NO_(2))underset(|)(C )-NHOH`