ABCD is a cyclic quadrilateral with AC being perpendicular to BD and O is the centre of its circumcircle, then

ABCD is a cyclic quadrilateral with AC being perpendicular to BD and O is the centre of its circumcircle, then

`\overrightarrow{"OA"}`.`\overrightarrow{"OB"}`+`\overrightarrow{"OB"}`.`\overrightarrow{"OC"}`+`\overrightarrow{"OC"}`.`\overrightarrow{"OD"}`+`\overrightarrow{"OD"}`.`\overrightarrow{"OA"}`

A. 1
B. -1
C. 0
D. 4

Correct answer is option C. 0Explanation: ABCD is a cyclic quadrilateral with AC being perpendicular to BD and O is the centre of its circumcircle, then it is equal to 0.