When a large amount of electrode paste is used to hold EEG electrodes in place, the total recording area will be:

The total recording area when a large amount of electrode paste is used to hold EEG electrodes in place corresponds to the scalp surface area of the paste. This is because the electrode paste not only facilitates adherence of the electrodes to the scalp but also enhances the conductivity of the electrical signals between the scalp and the electrodes.

When a significant amount of paste is applied, it creates a larger contact area with the scalp than just the diameter of the electrode itself. This expanded contact area improves the quality of the signal recorded and can minimize impedance, contributing to more accurate EEG readings.

Additionally, considerations such as the thickness and distribution of the paste can further affect the effective surface area in contact with the scalp, making option B the most comprehensive and accurate representation of the total recording area in this scenario.