### Instruction:

Extract the cause and effect entities from the following sentence:
The initial economic analysis showed that a positive business case for an L-band system implementation could be achieved with a payback period of approximately four years (Ref

### Assistant:

CAUSE_1: a payback period of approximately four years
EFFECT_1: a positive business case for an L-band system implementation could be achieved
NOT_RELEVANT: (Ref.
VARIABLE: a payback period
CONDITION: could be achieved
KEYWORD: with

