How is an identity verified with trigonometry?

Verify the following identity. tan -0 - 1 - cos 20 = 1+ tan 2 0 Which of the following four statements establishes the identity? tan 2 0 -1 tan 20 -1 O A. - cos 20 = sin 20 - cos 2 0= sec 2 0 1 + tan 2 0 tan - 0 -1 tan 2 0 -1 O B. - cos 20 = - 2 sin 0 cos 0 = = sec 2 0 1 + tan 2 0 tan 2 0 -1 tan 2 0 - 1 O C. - cos 20 = - 2 sin 0 cos 0 = = csc 2 0 1 + tan 2 0 tan 2 0 -1 tan 20 -1 O D. - cos 20 = sin 20 - cos 2 0= csc 2 0 1 + tan 2 0