For an Infinitely Repeated Game Promising a Per Period with Continuing

Multiple Choice

For an infinitely repeated game promising A per period with continuing cooperation,B for the one period gain from cheating and C per period for the non-cooperative solution (B > A > C) will have a subgame perfect Nash equilibrium in trigger strategies providing

A) δ > B/(A + C) .
B) δ > (B - A) /(B - C) .
C) δ > B/(A - C) .
D) δ > A/(B + C) .