In a dispute involving the retroactive application of 18 U. S. C. section 3582(c)(2) to plea agreements under FRCP 11(c)(1)(C), judgment of the appeals court affirming denial of defendant's motion for a reduction in sentence is reversed, because defendants who enter into 11(c)(1)(C) agreements that specify a particular sentence as a condition of the guilty plea may be eligible for relief under section 3582(c)(2).