I know that the rare earth elements (rare earths) - a group of 17 elements consisting of lanthanum, scandium, yttrium and the lanthanides. All these elements - metals silver-white color, while all have similar chemical properties (most common in oxidation state +3). The name "rare earth" is defined in connection with the fact that they are, first, relatively rare in the crust (the content of (1.6-1.7) x 10-2% by weight) and, secondly, to form a refractory substantially water-insoluble oxides (oxides of these at the beginning of the XIX century and formerly known as "lands").
That is why the correct answer is D)