The answer is D. The cold fusion theory was first brought about by Stanley Pons and Martin Fleischmann in 1989. They claimed that their unintended experiment has produced enormous amounts energy at room temperatures that could only be explained by cold fusion theory. The experiment involved the electrolysis of heavy water (with deuterium rather than hydrogen isotope) on a palladium (Pd) electrode. Their claims had brought immense attention by scientists, however, subsequent replicative experiments attempts failed and some discredited the initial experiment.
Many compunds have a terminal carbonyl
Aldehyde, Ketone, Carboxylic acid, Amide, Imide, Acid anhydride are the first that come to my mind.
All solutions are mixtures of two or more substances, but unless the mixture has a homogeneous distribution of solutes in the solvent, then the mixture is not a solution. Therefore, all mixtures are not solutions.
Hydrogen bonding and dipole-dipole forces.