Look at the diagram of an electrochemical cell below. (picture below) which part of the cell is the anode? na+ so42- nickel electrode platinum electrode

The correct option is NICKEL ELECTRODE.
In an electrochemical cell, there are always two electrodes, the anode and the cathode. The anode is the positively electrode through which the electrons leave the chemical device. In the set up given in this question, the nickel electrode is the anode while the platinum electrode is the cathode. You can easily see this from the half equations that are given in the question.

"C. nickel electrode" is the correct answer