Manafort to Cooperate With Mueller as Part of Guilty Plea

The transcript discusses the plea deal of Paul Manafort, who was in legal trouble with multiple felony charges. He agreed to cooperate with Robert Mueller's team, leading to the dropping of some charges. Manafort pleaded guilty to conspiracy against the United States and conspiracy to obstruct justice. His cooperation will be considered during sentencing, which is yet to be scheduled.

What options were available to Manafort aside from cooperating?

How might Manafort's cooperation affect his sentencing?