**From statement A alone.**Let the integers be in AP with the first term

*a* and common difference

*d*.

*n*^{th} term of the AP =

*T*_{n} =

*a* + (

*n* − 1)

*d* The value of the common difference,

*d*, is known but the value of the first term,

*a*, is not known.

∴ We cannot find the average of the first

*n* − 1 integers on the basis of this statement alone.

∴ Statement alone A is insufficient.

From statement B alone.*A* is the coefficient of the second highest power of

*x* in the given equation.

∴ −

*A* is the sum the

*n* roots of the given equation

∴ −

*A* is the sum the

*n* integers of the given set.

We need to know the

*n*^{th} integer of the set, to find the average of the first

*n* − 1 integers of the set.

∴ Statement B alone is insufficient.

**Combining statement A and B.** We find that we know both the sum and the common difference of

*n* integers in AP.

∴ We can calculate first term

*a*.

∴ We can calculate the

*n* integers of the set.

But neither its is given that the set is arranged in ascending or descending order nor do we know the

*n*^{th }element of the set.

∴ We cannot find the average of first

*n* − 1 integers of the set using statements A and B both.

Hence, option 5.