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

A chemical reagent known as Fehling's solution is used to differentiate between ketone and aldehyde functional groups.  Only aldehydes give red colour precipitate with Fehling's solution. 

The reaction between an aldehyde and the copper (II) ions in Fehling’s solution may be written as:

$\mathrm{RCHO} + 2{\mathrm{Cu}}^{2+}+\mathrm{SO}{\mathrm{H}}^{-}\underset{ }{\to }{\mathrm{RCOO}}^{-}+ \underset{\mathrm{Red} \mathrm{ppt}.}{{\mathrm{Cu}}_2\mathrm{O} }+3{\mathrm{H}}_2\mathrm{O}$

Hence , the correct option is (A) . $C{u}_{2}O$