I agree with Scott - thumbs up. You could also say "appears to relate to". "to be relating to" is not a passive form but it is still wrong because the continuous form of an infinitive (to be + -ing) is used with dynamic verbs, to describe something happening now or around now (just like the usage of the present continuous tense). "relate" is often used to indicate a permanent state or fact. The present simple infinitive ("to relate to) "or "to be related to" ("related" as participial adjective) would be the correct options. Thumbs down also for Najmieh because the usages of "distribution" and "that" in this sentence are correct. I can explain if necessary.

diffusion of copper, like gold has no relation to any kind of rocks. Or diffusion of copper, like gold has no relation to any particular rock. 1.distribution is for sth to be distributed but copper does this by itself . 2. "that" is a redundancy no need to that 3."to be relating " is passive form and make it unnecessarily too complicated .

I'm pretty sure the answer is, c. to be relating , but I'm having difficulty explaining why. Below is the correction: the distribution of copper, like that of gold, does not appear to be related to any particular type of rock

thanks for all of yours opinion but i haven't got it clearly. Quite a difficult excercise that my teacher gave. And the answer in my book is " like that "- wrong?? i think "to be relating to" is not wrong cause maybe author want to describe it happening