●Projection welding can be considered as the modification of spot welding.

●Projection welding is a variation of the spot welding in which small projection are made in one of the surfaces. Then, the parts to be welded are clamped between the flat copper alloy electrodes. On the passage of a high current, the projections melt and form the weld. The process is obviously suitable for a sheet metal assembly, and, unlike spot welding, leaves no indentation mark on the free surfaces.

●In most applications multiple small projections are formed on one surface of the parts to be welded. So, Projection welding is considered as multi-spot welding process.

Hence, the correct option is (A).