How could you describe the changes that happen when carbon changes form from graphite to diamond?

The answer for #3 is c but i don't know why

8) a mixture of he, ne and ar has a pressure of 7.85 atm. if the ne has a mole fraction of 0.47 and 8) ar has a mole fraction of 0.23, what is the pressure of he? a) 4.2 atm b) 3.7 atm c) 5.5 atm d) 2.4 atm e) 1.8 atm

Which type of intermolecular force is pbr3