Three vectors \(A,B\) and \(C\) add up to zero. Then:
1. vector \((A\times B)\times C\) is not zero unless vectors \(B\) and \(C\) are parallel.
2. vector \((A\times B).C\) is not zero unless vectors \(B\) and \(C\) are parallel.
3. if vectors \(A,B\) and \(C\) define a plane, \((A\times B)\times C\) is in that plane.
4. \((A\times B). C= |A||B||C|\rightarrow C^2= A^2+B^2\)

The incorrect statement/s is/are:
1. (b), (d)
2. (a), (c)
3. (b), (c), (d)
4. (a), (b)

(1) Hint: The resultant of three vectors will be equal to zero only if the vectors are coplanar.

Step 1: Find if the vectors are coplanar.

Given, A + B + C = 0

Hence, we can say that A, B, and C are in one plane and are represented by the three sides of a triangle taken in one order.
Step 2: Find the incorrect statements one by one.

      B×(A+B+C)=B×0=0 B×A+B×B+B×C=0 B×A+0+B×C=0 B×A=B×C A×B=B×C (A×B)×C=(B×C)×C

It cannot be zero as (B×C)×C can not be zero unless B and C are parallel to each other. Hence statement (a) is correct.

If B and C are not parallel, then (AxB) will be perpendicular to the plane of A, B and C.
Hence, (AxB).C = 0 whatever be the situation is. Hence, statement (b) is incorrect and option.
Also, (AxB)xC
will be in the plane of A, B and C and statement (c) is correct.
Statement (d) is also incorrect as discussed already.