(A) In the given electrochemical cell (Daniell cell),the $Zn$ electrode acts as the anode (negative terminal) and the $Cu$ electrode acts as the cathode (positive terminal).
The electrode $A$ is connected to the $Zn$ electrode of the electrochemical cell. Since the $Zn$ electrode is the negative terminal,the electrode $A$ becomes the positive terminal (anode) of the electrolytic cell.
The electrode $B$ is connected to the $Cu$ electrode of the electrochemical cell. Since the $Cu$ electrode is the positive terminal,the electrode $B$ becomes the negative terminal (cathode) of the electrolytic cell.
Therefore,electrode $A$ is positive and electrode $B$ is negative.