Hunter: Hunters alone are blamed for the decline in Greenrock National Forest' s deer population over the past ten years. Yet clearly, <b> black bears have also played an important role in this decline </b>. In the past ten years, the forest' s protected black bear population has risen sharply, and examination of black bears found dead in the forest during the deer hunting season showed that a number of them had recently fed on deer. In the hunter's argument, the boldface portion plays which of the following roles? ['It is a finding that the argument seeks to explain.', 'It is a judgment that the argument opposes.', 'It is an objection that has been raised against the main conclusion of the argument.', 'It is the main conclusion of the argument.']