The correct option is A - c
Well, in this problem we will be using two properties.
We know cot−1(x)=tan−1(1x)cot−1(0.2)=tan−1(10.2)=tan−1(5)So,tan−1(5)=cBut we are asked to find tan−1(5)
We know one more property of inverse trigonometric functions. Well, this is not just the property of inverse trigonometric functions. This is the property of odd functions according to which -
tan−1(−x)= −tan−1 (x)(Since, tan−1(x) is an odd function)So,tan−1(−5)=−tan−1(5)=−c