Which of the following is true of organic compounds? they always contain hydrogen. each has distinctive chemical and physical properties. they are only found in living things. they cannot be synthesized.

Option A is incorrect because there are many organic compounds which does not contain hydrogen atom like Tetrachloromethane (CCl₄), Phosgene (COCl₂) e.t.c.

Option C is incorrect because many organic compounds are found in soil, rocks, mountains particularly the fossil fuels e.t.c.

Option D is also incorrect because organic compounds can be synthesized. Example is the drug store in your town.

Option B is correct because organic compounds with different functional groups have different chemical and physical properties.