The correct option is A →a,→b,→c are orthogonal in pairs and |→a|=|→b| and |→c|=1
→c=→a×→b⇒→c⊥→aand →c⊥→b→a=→b×→c⇒→a⊥→band →a⊥→c}⇒→a⊥→b⊥→c
Now,→a×→b=→c
⇒(→b×→c)×→b=→c[since →a=→b×→c]⇒(→b.→b)→c−(→b.→c)→b=→c⇒|→b|2→c=→c[→b⊥→c,∴→b.→c=0]⇒|→b|=1
Also, →c=→a×→b
⇒|→c|=|→a×→b|⇒|→c|=|→a|×|→b|sinπ2⇒|→c|=|→a|(∴|→b|=1)