When acetaldehyde is heated with Fehling solution, a red precipitate is formed. Which of the following is that ?

Fehling's A is a solution containing copper(II) sulphate, which is blue color. Fehling's B is a clear liquid consisting of potassium sodium tartrate (Rochelle salt) and a strong alkali like NaOH,KOH.,Etc, usually sodium hydroxide. During the test solutions A and B are prepared individually and stored. Just before the test they are mixed. Aldehyde give red ppt and ketones do not respond. Cu(II) is converted into Cu(I) red color.