The threads of a screw used to fasten two pieces of wood are pitched at an angle. How does this increase the static friction force?

Question

By decreasing the coefficient of static friction between the screw and the wood%0D%0ABy decreasing the coefficient of static friction between the screw and the wood%0D%0A%0D%0ABy increasing the ease of inserting the screw into the wood%0D%0ABy increasing the ease of inserting the screw into the wood%0D%0A%0D%0ABy increasing the normal force exerted by the wood on the screw thread%0D%0ABy increasing the normal force exerted by the wood on the screw thread%0D%0A%0D%0ABy decreasing the surface area between the screw surface and the wood

Answer 1

By increasing the normal force exerted by the wood on the screw thread