We have to know which of the given statement is not true of carbon.
Not true statement of carbon is - it forms strong ionic bonds.
It can not form ionic bond. to produce ionic bond, carbon has to be converted into either C⁴⁺ or C⁴⁻.
The electronic configuration of C-atom is 1s²2s²2p⁴.
To form C⁴⁺ cation, four electrons must be removed from outermost shell of carbon atom which requires huge energy to supply.
To form C⁴⁻ anion, four electrons must be added to outermost shell of carbon atom which is not possible as outermost shell of C-atom does not have 2d orbital to accommodate extra electrons.