There are a number of possible methods to control an invasion of gypsy moths in a city park. Several alternatives are listed below. a ) A band of material can be placed around each tree trunk, preventing the larvae from crawling up the trunk. The larvae can be picked off by hand each day and destroyed. b )A chemical insecticide can be sprayed from an airplane. The chemical is effective and disappears rapidly, although some may run off into ponds and lakes. c) The trees can be sprayed with a liquid containing naturally occurring bacteria that feed on gypsy moths. These bacteria are believed to be harmless, but the spray is very expensive. d) No action is taken. This allows nature to take its course, which results in major changes in the area concerned. The damage can then be repaired. Write the letter of the method you would use and give an ecologically sound reason for your choice.