The following bond has highest bond energy ?

• For covalent molecules, the bond energy is directly proportional to the electronegativity of the atoms and inversely proportional to the bond length.
•  Down the group, the E.N. of an atom decreases, and the size increases, which results in a decrease in the bond energy.

              Thus, the bond energy will be,

                          C−C>Si−Si>Ge−Ge>Sn−Sn