Having trouble with this one; I've tried working backwards from the three carbon carboxylic acid product, but to no avail. Please help!! I can not figure out 'K'. "A hydrocarbon K adds one equivalent of H2 upon hydrogenation over a Pt catalyst. When K is oxidized vigorously with hot KMnO4, a single three carbon carboxylic acid is obtained. Give the structures of K and the carboxylic acid." This seems simple but K is giving me a lot of grief.