A lightning rod with sharp tip reduces damage risk. Which one of the following is the primary reason for it?

A sharp pointed conductor concentrates surface charge density at the tip (since charge accumulates on regions of high curvature), producing a very strong local electric field. This intense field ionises the surrounding air and produces a continuous corona discharge, which gradually neutralises the charge in the nearby clouds and leaks charge from the rod to the air. This bleeds away potential difference before a full lightning strike can develop, thereby reducing damage risk. It is not about attracting or repelling clouds.