Q. Multi-electrode resistivity survey is carried out by placing 10 equispaced electrodes (denoted by arrows in the figure below) on the surface of the earth. The points of observations in the distance-apparent depth plane are marked as solid dots in the figure shown below. Considering the mid-point of the 4-electrode array as the point of observation in the lateral direction, identify the CORRECT electrode configuration used for the survey.
A. Multi-electrode Wenner array.
B. Multi-electrode Axial Dipole-dipole array.
C. Multi-electrode Wenner-Schlumberger array.
D. Multi-electrode Axial Pole-dipole array.