The correct option is B coplanar
Let p=→a×(→b×→c)
q=→b×(→c×→a)
r=→c×(→a×→b)
p+q+r=→a×(→b×→c)+→b×(→c×→a)+→c×(→a×→b)
= {(a . c) – (a . b)c} + {(b . a)c – (b . c)a} + {(c . b)a – (c . a)b}
= {(a . c)b – (a . b)c + (a . b)c – (b . c)a + (b . c)a – (a . c)b}
= 0
So p + q + r = 0
or p=(−1)×q+(−1)×r
So p is a linear combination of q and r.
So they are coplanar.