The correct option is C →0
Given (→a×→c) is perpendicular to (→a×(→b×→c))⇒(→a×(→b×→c))⋅(→a×→c)=0 ⇒[(→a⋅→c)→b−(→a⋅→b)→c]⋅(→a×→c)=0⇒(→a⋅→c)[→b →a →c]=0 (As →a,→b and →c are non-coplanar vectors.
So, [→b →a →c]≠0 )
∴(→a⋅→c)=0
Now, →a×(→b×→c)=(→a⋅→c)→b−(→a⋅→b)→c
⇒→a×(→b×→c)=−(→a⋅→b)→c
⇒[→a×(→b×→c)]×→c=−(→a⋅→b)(→c×→c)=→0