Given three non-coplanar vectors OA=a, OB=b, OC=c. Let S be the centre of the sphere passing through the points O, A, B, C if OS=x, then

Options

A. x must be linear combination of a, b, c
B. x must be linear combination of `btimesc, ctimesa and atimesb`
C. `x=(a^(2)(btimesc)+b^(2)(ctimesa)+c^(2)(atimesb))/(2[a b c]), a=|a|, b=|b|. C=|c|`
D. `x=a+b+c`

Answer

A, B, C