How do carbon atoms form many organic compounds

Carbon has four valence electrons, so it can achieve a full outer energy level by forming four covalent bonds. When it bonds only with hydrogen, it forms compounds called hydrocarbons. Carbon can form single, double, or triple covalent bonds with other carbon atoms.

a wrong

b wrong

c right

d wrong

the correct answer would be b) volume versus temperature, because they are also directly proportional.