The Image Shows Bonding for Diamond on the Left) and Graphite

Multiple Choice

The image shows bonding for diamond on the left) and graphite on the right) . Both minerals are made of carbon, so why do they have very different properties why is diamond so hard while graphite is so soft) ?

A) Covalent bonds in both minerals are very strong, but intermolecular bonds between sheets in graphite are very weak.
B) Graphite's mixture of covalent and intermolecular bonds is stronger than the solely covalent bonds within diamond.
C) Diamond has a different type of covalent bonds between the atoms of carbon than does graphite.
D) Minerals with only one type of bond will always be harder than minerals that have two different types of bonding.