Describe a Sigmatropic Rearrangement

Describe a sigmatropic rearrangement.

A) A sigma bond in the reactant has moved to a different location in the product,and the pi bonds have rearranged.
B) The product contains a new ring,with two less sigma bonds,and two more pi bonds than the starting material.
C) The product contains a new ring,with two more sigma bonds,and two less pi bonds than the starting material.
D) The product contains a new ring,with one less sigma bond,and one more pi bond than the starting material.
E) The product contains a new ring,with one more sigma bond,and one less pi bond than the starting material.