What is the test for ineffective assistance of counsel?

We apply settled standards to determine whether defense counsel rendered ineffective assistance of counsel during closing argument. " 'In assessing claims of ineffective assistance of trial counsel, we consider whether counsel's representation fell below an objective standard of reasonableness under prevailing professional norms and whether the defendant suffered prejudice to a reasonable probability, that is a probability sufficient to undermine confidence in the outcome. [Citations.] A reviewing court will indulge in a presumption that counsel's performance fell within the wide range of professional competence and that counsel actions and inactions can be explained as a matter of sound trial strategy. Defendant thus bears the burden of establishing constitutionally inadequate assistance of counsel. [Citations.] If the record on appeal sheds no light on why counsel acted or failed to act in the manner challenged, an appellate claim of ineffective assistance of counsel must be rejected unless counsel was asked for an explanation and failed to provide one, or there simply could be no satisfactory explanation. [Citations.]' These standards apply with particular force at closing argument because, as we have recognized, '[t]he decision of how to argue to the jury after the presentation of evidence is inherently tactical . . . .' " (People v. Gamache (2010) 48 Cal.4th 347, 391, italics added.)