If the roots of equation \({x^3} - 12{x^2} + 39x - 28 = 0\) are in A.P., then the common difference of the A. P. is:

If the roots of equation \({x^3} - 12{x^2} + 39x - 28 = 0\) are in A

1.	If the roots of equation \({x^3} - 12{x^2} + 39x - 28 = 0\) are in A.P., then the common difference of the A. P. is:
A.	12
B.	-12
C.	39
D.	3
Answer» E.