1) If |→a|=3|→b|=2,|→c|=1 then the value of |→a.→b+→b.→c+→c.→a| is (given that →a+→b+→c=0 ) A) -7 B) 7 C) 14 D) -14 Answer: Option BExplanation:→a+→b+→c=0 ⇒(→a+→b+→c)2=0 ⇒|→a|2+|→b|2+|→c|2+2(→a.→b+→b.→c+→c.→a)=0 ⇒9+4+1+2(→a.→b+→b.→c+→c.→a)=0 ⇒→a.→b+→b.→c+→c.→a=7