What is the basis for the difference in the synthesis of the leading and lagging strand of DNA molecules?

Options

A. Origin of replication occurs only at the 5' end of the molecules?
B. DNA ligase works only in the `3' rarr 5'` direction.
C. DNA polymerase cacn jooin new nucleotides only to the 3' end of the growing strand .
D. Helicases and single-strand binding proteins that work at the 5' end.