Amongs the following which is redox reaction ?
A. formation of ozone from atmospheric oxygen in the presence of sunlight
B. reaction of `H_(2)SO_(4)` with `NaOH` reaction of `[Co(H_(2)O)_(6)]Cl_(3)` with `AgNO_(3)`
C. combination of dinitrogen with dioxygen at 2000 K
D.