The value of cot 10°.cot 20°.cot 60°.cot 70°.cot 80° is?

Answer: Option D

cot10° .cot20° .cot60°.cot70° .cot80°
[ In cot A.cot B if A + B = 90° then cot A.cot B = 1 ]
(cot10° .cot80°) × (cot20°.cot70°) × cot60°
∴ 1 × 1 × $$\frac{1}{\sqrt{3}}$$
= $$\frac{1}{\sqrt{3}}$$