The Recurrence Relation for the Power Series Solution About $x = 0$

Multiple Choice

The recurrence relation for the power series solution about $x = 0$ of the differential equation $y ^ { \prime \prime } - y = 0$ is (for $k = 0,1,2 , \ldots$ )

A) $( k + 2 ) ( k + 1 ) c _ { k + 2 } = c _ { k }$
B) $( k + 2 ) ( k + 1 ) c _ { k } = c _ { k - 2 }$
C) $( k + 1 ) k c _ { k + 2 } = c _ { k }$
D) $( k + 1 ) k c _ { k } = c _ { k - 2 }$
E) $( k - 2 ) ( k - 1 ) c _ { k - 2 } = c _ { k }$